Beijing responded swiftly on Tuesday to the tariffs President Trump had promised, announcing a fusillade of countermeasures targeting American companies and imports of critical products.

Mr. Trump’s 10 percent tariff on all Chinese products went into effect at 12:01 a.m. Tuesday, the result of an executive order issued over the weekend aimed at pressuring Beijing to crack down on fentanyl shipments into the United States.

The Chinese government came back with a series of retaliatory steps, including additional tariffs on liquefied natural gas, coal, farm machinery and other products from the United States, which will take effect next Monday. It also immediately implemented restrictions on the export of certain critical minerals, many of which are used in the production of high-tech products.

In addition, Chinese market regulators said they had launched an antimonopoly investigation into Google. Google is blocked from China’s internet, but the move may disrupt the company’s dealings with Chinese companies.

Wendy Cutler, a former U.S. trade negotiator, said the various measures were a signal from China of the range of options it has to respond to Mr. Trump’s trade actions. “This menu approach is not surprising,” she said. “Beijing has been building its toolbox for some time.”

The U.S. tariffs, which Mr. Trump said on Monday were an “opening salvo,” come on top of levies that the president imposed during his first term. Many Chinese products already faced a 10 or 25 percent tariff, and the move adds a 10 percent tariff to more than $400 billion of goods that Americans purchase from China each year, particularly impacting computers and electronics, electrical equipment, and clothing.

Mr. Trump had been planning to hit America’s three largest trading partners, Canada, Mexico and China, with tariffs of varying degrees. But after days of frantic negotiations, Mr. Trump agreed to pause the tariffs on Mexico and Canada for 30 days after the Canadian and Mexican governments promised to step up their oversight of fentanyl and the border.

The president has not yet had similar conversations with China’s top leaders. On Tuesday afternoon, Mr. Trump said that he would speak with Chinese leader Xi Jinping at “the appropriate time” and that he was “in no rush.”

China’s counterpunches suggested an effort to hurt American businesses and send a warning to the Trump administration, while holding in reserve measures that could do even more serious damage to trade between the world’s two biggest economies. But some trade experts said China had reserved the right to grant exemptions to its tariffs, and were calibrated to send the Trump administration a message without causing too much damage.

Researchers at Capital Economics calculated that the Chinese tariffs would hit about $20 billion of U.S. exports — about 12 percent of what the United States sends to China each year — far less than the more than $450 billion worth of Chinese imports taxed by the United States. They also said it was notable that no strategic items China imports from the United States — like high-end chips, pharmaceuticals or aerospace equipment — were targeted.

“As far as I can see so far, it’s a relatively limited response, affecting no more than 30 percent of U.S. exports to China,” said Bert Hofman, a former World Bank official and now an adjunct professor at the East Asian Institute at the National University of Singapore. “They’re probably trying to keep their powder dry, because this could still be only the first step from the Trump administration.”

The Trump administration’s tariffs “seriously undermine the rules-based multilateral trading system, damage the foundation of economic and trade cooperation between China and the United States, and disrupt the stability of global industry supply chains,” China’s Ministry of Commerce said in a statement.

The commerce ministry and China’s customs agency announced new restrictions on exports of tungsten, tellurium, molybdenum and other metals important for industry and new technologies, citing “national security and interests.”

Stephen Orlins, the president of the National Committee on United States–China Relations, said that the Chinese response was “measured,” but that the decision to extend curbs on critical minerals was “unwise.”

“It reminds Americans that the supply chain is not reliable,” he said.

China’s measures included an additional 10 percent tariff on crude oil, agricultural equipment, larger cars and pickup trucks, as well as an additional 15 percent tariff on coal and natural gas, the Chinese tax authorities announced. Those tariffs will go into effect Feb. 10.

China also said it had added two American companies to its “unreliable entities” list. One of the companies, PVH — the American retailer that owns the Calvin Klein and Tommy Hilfiger brands — had already been placed under investigation by Chinese regulators in September. China said PVH had taken “discriminatory measures” against goods from the Xinjiang region in China’s far west.

Google did not immediately respond to a request for comment on the announcement of the antitrust investigation.

While Google dominates the world in digital advertising and internet search, restrictions in China mean it cannot operate its search engine, its YouTube video platform or its app store, Google Play, in the country. Still, its operating system, Android, is used by some Chinese phone makers, including Xiaomi, Lenovo and Vivo. Regulators around the world, including ones in the United States, Canada, Europe and South Korea, have probed Google on antitrust grounds or brought related cases.

Christine McDaniel, a research fellow with the Mercatus Center, said a 10 percent tariff was not huge, and could likely be absorbed by importers and exporters without extreme pain. U.S. agriculture is vulnerable to retaliation though, she said, and the tariffs “put everyone on notice” that they could escalate.

Besides imposing his new tariffs, Mr. Trump’s executive order, signed on Saturday, ended a popular workaround that many Chinese companies had used to send goods to the United States without paying the tariffs that the president imposed in 2018. The provision, known as de minimis, allowed popular e-commerce companies like Shein and Temu to send billions of dollars of products from Chinese factories directly to American consumers without tariffs.

The deals that Mr. Trump made with Canada and Mexico on Monday brought the United States back from the brink of a potentially devastating trade war with two of its closest allies. But it did not preclude the threat of similar conflicts happening later.

On Monday, Mr. Trump made clear that he would deploy tariffs liberally to get other governments to give him what he wants.

Mr. Trump has accused China of failing to do enough to stop the export of fentanyl and the chemicals that are used to make it. In the executive order he issued on Saturday, Mr. Trump said that shipments of synthetic opioids had ravaged U.S. communities, put a severe strain on the health care system and were the leading cause of death for people aged 18 to 45 in the United States.

It’s not clear what steps the Chinese government has recently taken, if any, to restrict the fentanyl trade, beyond its previous law enforcement collaboration with the United States. Mr. Trump discussed fentanyl with Mr. Xi in a phone call during his first week in office.

During Mr. Trump’s first term, China introduced a ban on fentanyl and began working with the United States to catch traffickers, under pressure from Mr. Trump. And in 2023, Mr. Xi and then-President Joseph R. Biden Jr. agreed to a series of bilateral talks on narcotics after they met in Woodside, Calif.

A spokesman for the Chinese Embassy in Washington had said that China firmly opposed tariffs and that any differences or frictions should be resolved through dialogue. “There is no winner in a trade war or tariff war, which serves the interests of neither side nor the world,” the spokesman said.

Mr. Trump waged an intense trade war with China during his first term, after initiating a trade case that found that the country had unfairly infringed on U.S. intellectual property. He ratcheted up tariffs on China and ultimately applied tariffs to about 60 percent of the country’s exports to the United States.

Now Mr. Trump, in office for two weeks, has initiated a new exchange with China.

“This is likely only the beginning of a long process for the two countries to negotiate,” Zhiwei Zhang, the president and chief economist of Pinpoint Asset Management, an investment firm in Hong Kong, said in written comments. “There is hope to de-escalate in this process, though the road ahead may be bumpy.”

Claire Fu contributed reporting from Seoul, Amy Chang Chien from Taipei, Taiwan, and Nico Grant from San Francisco.

As President Trump was locked in a war of words with the leader of Colombia over the military deportation of migrants, China’s ambassador to Colombia declared that relations between Beijing and Bogotá were at their “best moment” in decades.

Zhu Jingyang, the ambassador, later said that it was a coincidence that he posted his comment on social media last week, a day after Mr. Trump said he would slap tariffs on Colombia. But the public outreach suggested that Beijing saw an opportunity to strengthen its hand in the high-stakes superpower rivalry between China and the United States.

Two weeks into the second Trump administration, Mr. Trump’s aggressive “America First” foreign policy holds both promise and peril for Beijing.

The perils have always been clear: more tariffs, and the risk of a wider trade war. This weekend, Mr. Trump imposed an additional 10 percent tariffs on goods imported from China, saying the tariffs were a response to China’s failure to curb fentanyl exports. He could answer any retaliation from China with even higher levies.

But even as Beijing calculates the impact of the tariffs on China’s weak economy, it is surely also taking stock of the openings that Mr. Trump’s other moves are giving China.

Mr. Trump has alienated U.S. allies and partners like Canada and Mexico by imposing steep tariffs on their exports. He has weakened America’s global authority by cutting foreign aid and withdrawing from the World Health Organization and the Paris Agreement, a U.N. climate pact.

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It’s been called the Trump playbook, the Trump card, the Trumpist approach, campaigning as “Donald Trump lite” and even “going full Trump.”

Election season is heating up in Australia, where the opposition leader, Peter Dutton, has been sounding a lot like President Trump. He has lashed out at a “woke brigade” of banks, grocery stores and a chain of pubs for addressing environmental and Indigenous issues. He has lamented about young men being “disenfranchised and ostracized” by diversity initiatives. And he’s set up a shadow minister for government efficiency.

Mr. Dutton, the head of Australia’s main center-right political party, hopes to oust Prime Minister Anthony Albanese in an election that must be held by May 17. Mr. Albanese has been under pressure to rein in post-pandemic inflation, and Mr. Dutton has accused him of being too distracted by “woke” issues, like Indigenous rights, to address high prices and unaffordable housing.

Mr. Albanese has rolled out a tax cut and said the government was getting a handle on underlying inflation, which has fallen to a three-year low of 3.2 percent.

But last week, a widely followed poll had Mr. Albanese’s approval rating at its lowest point since he came to power in 2022. Fifty-seven percent of respondents in the NewsPoll survey said they disapproved of his performance. A head-to-head comparison showed Mr. Dutton closing in on Mr. Albanese, a sign that his political messaging was getting at least some traction.

“What I like about Dutton is he doesn’t sit on the fence,” said Louise Pridham, 57, a retired nurse who lives in the Sydney suburb of Cronulla. She and her husband, Nigel Pridham, a 57-year-old builder, said they were not Trump fans but felt validated by some of Mr. Dutton’s messaging, which Mr. Pridham acknowledged had a Trump-like quality.

Ms. Pridham said more people she knew seemed to be appreciating Mr. Dutton’s bluntness. “He says as it is. There’s no wokeness in it.”

The parallels between Mr. Trump and Mr. Dutton, a 57-year-old former policeman known for his tough stances on immigration and asylum seekers, are drawn by both supporters and critics. Mr. Dutton has not shied away from the allusion; on Friday, he railed about the government’s diversity and inclusion efforts, hours after Mr. Trump, without offering evidence, blamed D.E.I. policies for a deadly plane-helicopter collision outside Washington.

“Positions advertised have included culture, diversity and inclusion advisers, change managers and internal communication specialists,” Mr. Dutton said, referring to job openings in the government. “Such positions, as I say, do nothing to improve the lives of everyday Australians.”

Mr. Dutton’s office did not respond to requests for comment.

Mr. Trump’s return to office has emboldened a range of right-wing politicians across Europe to harden their rhetoric, solidify their bases and expand their ambitions.

But in Australia, the influences are more muddled. In 2019, a survey found that the conservative base in Australia was far more ideologically aligned with Hillary Clinton backers in the United States than with Trump supporters. Last year, barely a fifth of Australian voters said in a survey that they would have chosen Mr. Trump over then-Vice President Kamala Harris if the U.S. election were up to them.

Mr. Dutton made clear his distaste for “wokeness” as early as 2021, when as defense minister he banned events where staff members wore rainbow-colored clothing to support L.G.B.T.Q. awareness.

Two years later, conservatives were energized by a watershed moment in Australia’s culture wars. In 2023, a proposal to give Indigenous Australians a voice in Parliament in the form of an advisory body was rejected soundly by voters in a referendum. It had been a landmark effort for Mr. Albanese, and its defeat, his opponents argued, meant a majority of Australians felt that placing too much emphasis on the country’s colonial sins was divisive.

One of Mr. Dutton’s rallying cries has been his defense of Australia Day, the annual Jan. 26 holiday marking the day British settlers first landed in the Sydney area. In recent years, people who see it as a celebration of brutal colonial oppression of the Aboriginal population have called for abolishing the holiday or moving it to a different date.

But a survey conducted last month by The Sydney Morning Herald found that 61 percent of Australians supported keeping Australia Day as it is, up from 47 percent a year earlier.

Mark Kenny, the director of the Australian Studies Institute at the Australian National University, said Mr. Dutton’s rhetoric appealed to a working-class base, which, like its American counterpart, sees itself as having been abandoned by economic shifts, including the decline of manufacturing. Those voters felt let down by their traditional political leadership on the left, he said.

“What you’ve got there is a kind of long-simmering sense of dissatisfaction, of being ignored, of not heard, being left behind,” he said. “When Dutton says ‘woke,’ it’s lazy and imprecise, but that doesn’t matter. People can attach to it what they think.”

It is unlikely that Mr. Dutton can win just by mobilizing single-issue voters. That’s because voting is compulsory in Australia, with the threat of a fine for noncompliance, and turnout typically exceeds 90 percent.

As readily as he has adopted some of Mr. Trump’s language and priorities, Mr. Dutton has drawn the line at others, resisting pressure from a coalition partner to campaign on transgender issues. He has also indicated that he would not consider withdrawing Australia from the Paris Agreement, the international climate accord.

To Graeme Turner, emeritus professor of cultural studies at the University of Queensland, Mr. Dutton’s use of Mr. Trump’s words and rhetoric seem a lot more opportunistic than substantive.

“I doubt you could find a politician who could define the word ‘woke,’” Mr. Turner said. “It’s become a really handy slogan as a way of smearing any idea they don’t like, as a way of pre-empting it from serious analysis.”

The sniping over Australia Day continued last week. Sussan Ley, the deputy leader of Mr. Dutton’s party, marked the holiday by likening the arrival of British colonizers to Elon Musk’s ambitions to settle Mars. “They did not come to destroy or to pillage,” she said, in comments that were promptly criticized and lampooned.

The day before, at the spot where Captain James Cook first landed in Australia in 1770 — now a national park — a smattering of families sprawled out on grassy knolls and enjoyed a leisurely, sunny afternoon.

“It wouldn’t matter to me if you change the date because it’s not that big a deal,” John Gallop said of the holiday that was causing so much fuss among politicians. He said it was his first visit to the site in more than 50 years of living in Sydney, and that he had only come at the urging of his wife, who is from the Philippines.

“There’s so much more we need to change in Australia,” he said.

It was a brief remark during a mundane session of Parliament. But to Harini Amarasuriya, Sri Lanka’s prime minister, it was the moment she realized that her country, wrecked not long ago by strongman leaders and their populist politics, had entered a potentially transformative moment for women.

A male colleague (and “not a very feminist” one, as Dr. Amarasuriya described him) stood up to say that the island nation could not get more women into the formal work force unless it officially recognized the “care economy” — work caring for others.

To Dr. Amarasuriya, it was “one of the biggest thrills” to hear language in government that had long been confined to activists or to largely forgotten gender departments. “I was like, ‘OK, all those years of fighting with you have paid off,’” she said with a laugh during an interview in December at her office in Colombo, the capital.

Two years after Sri Lankans rose up and cast out a political dynasty whose profligacy had brought economic ruin, the country is in the midst of a once-in-a-lifetime reinvention.

Anger has steadied into a quieter resolve for wholesale change. Through a pair of national elections last year, for president and for Parliament, the old elite that had governed for decades was decimated. A leftist movement has risen in its place, promising a more equal society.

As the country’s democracy rebounds, opportunities are opening for women.

Prime Minister Justin Trudeau of Canada went for a threat of immediate retaliation and a late-night emotional address that produced a cliffhanger compromise.

President Claudia Sheinbaum of Mexico opted for carrots over sticks, and backroom talks that led to an early deal.

In the end, when all was said and done on Monday, hours before what would have been the start of a North American trade war, both leaders negotiated reprieves from President Trump on his threat to impose tariffs on the United States’ two top trading partners.

And both had to provide relatively little in exchange.

The different routes Mr. Trudeau and Ms. Sheinbaum followed to the same outcome — a 30-day delay in U.S. tariffs in exchange for toughening their borders to stem the flow of drugs and unauthorized migrants into the United States — tell a tale of two different styles of leadership, and two countries with different relationships to the United States.

Mr. Trudeau had been preparing the ground for compromise — and retaliation — since November. Three days after Mr. Trump first issued his tariff threat on Nov. 25, the Canadian prime minister got on a plane to Mar-a-Lago to talk to him about averting what would amount to a fraternal trade war that would deeply hurt the Canadian economy.

By all accounts, that first meeting set the scene for Canada’s groundwork to directly address what Mr. Trump said he wanted: a safer northern border, with fewer unauthorized migrant crossings, and a tighter grip on fentanyl flowing across the border.

The parallel story of how Mexico’s leader got the same tariff delay for her country, with a few hours’ advantage over Canada, highlights Ms. Sheinbaum’s choice to focus on partnership in her talks with Mr. Trump and not reach for a swift retaliation.

Even before being voted into office in June, Ms. Sheinbaum and her team had been preparing for the possibility that Mr. Trump would return to the White House. And since his victory in November, Ms. Sheinbaum has reiterated that she wasn’t concerned despite his threats of mass deportations and tariffs. The day after the U.S. elections, she promised to “establish communication and good relations.”

In Canada, the weeks since the meeting at Mar-a-Lago between Mr. Trudeau and Mr. Trump have been packed with developments that normally take months, or even years, to unfold. For starters, Mr. Trudeau, who has become increasingly unpopular at home, announced that he would resign. On March 9 his party, the Liberals, will elect a new leader and that person will become Canada’s next prime minister, at least until a federal election is called later this year.

Several of his top ministers said they would not run to replace him in order to focus on the looming tariff showdown. The foreign minister, Mélanie Joly, and the finance minister, Dominic LeBlanc, both close Trudeau allies and potential successors, instead threw themselves at lobbying key Republicans.

Mr. LeBlanc developed a “bromance” with Howard Lutnick, Mr. Trump’s pick to be commerce secretary. Ms. Joly visited the United States five times, lobbying senior Republicans and talking to Mr. Trump’s border czar, Thomas Homan.

She told them that Canada would take the lead in protecting the border so that the United States would not need to use too many resources.

“I said, we know that the southern border is a preoccupation for you, so we will put the resources at the northern border,” Ms. Joly said in an interview about her message to Republicans she met. “That way you can have your resources at the southern border.”

But Mr. Trudeau also made it clear that he would level retaliatory tariffs against the United States if Mr. Trump decided to go ahead with his threat. Government officials said that the outgoing Canadian leader believed it was vital to stand up for Canada in a more aggressive way, while simultaneously working to satisfy Mr. Trump’s demands.

Canada in December rolled out, and budgeted for, a multiyear $900 million plan to bolster its border protections. That included immediately deploying two Blackhawk helicopters, 60 U.S.-made drones and additional border guards.

On Saturday, after the White House had announced that Mr. Trump would go ahead with the tariffs, Mr. Trudeau addressed not just Canadians, but also made clear he was speaking directly to Americans, in an emotional late-night speech.

“We don’t want to be here,” Mr. Trudeau said, evoking the deep bonds between the two neighbors and close trading partners. “We didn’t ask for this.”

But, as he detailed his own retaliatory tariff plan, he added: “We will stand strong for Canada.”

In the end, it came down to the wire. Mr. Trudeau and Mr. Trump failed to reach a compromise in a Monday morning call. That prolonged the anxiety for a few hours, but, a second call in the late afternoon yielded a deal, with Mr. Trump agreeing to push tariffs back by a month.

The foundations of the eventual deal announced on Monday afternoon had been in place for weeks, but Canada also pledged to do more on the fentanyl front, appointing a “fentanyl czar” and committing fresh resources to combating organized crime and cartels.

In Mexico, Ms. Sheinbaum’s predecessor and mentor, Andrés Manuel López Obrador, had forged a close working relationship with Mr. Trump in the early years of his administration, despite similar circumstances: Mr. Trump’s repeated threats to impose tariffs on Mexico and make the country pay for a border wall. In an effort to stave off levies, Mr. López Obrador agreed to bolster immigration enforcement, including deploying the National Guard.

Conditions, though, have changed since then. Mexico has eclipsed China as the largest trading partner in goods with the United States. And Mexico emerged as the top market worldwide for U.S. food and agriculture exports, with those imports surging to more than $29 billion.

But there is a key difference between Mr. López Obrador and Ms. Sheinbaum: While he at times adopted a confrontational tone toward the United States, she maintains a more measured and coolheaded demeanor.

Unlike Canada, which was clear both about its plans to retaliate with its own tariffs on U.S. goods and with its border plans to address Mr. Trump’s demands, Ms. Sheinbaum and her team were more tight-lipped.

After Mr. Trump ordered the tariffs on Saturday, Ms. Sheinbaum still bided her time, promising to reveal her “Plan B” response later — but she first asked that Mr. Trump respond to her request to form a working group of security and health officials from both countries.

Later that Saturday, Mr. Trudeau and Ms. Sheinbaum got on the phone to swap notes. A Canadian official with knowledge of the call said that they updated each other on their respective strategies, and acknowledged that they were slightly different approaches, but had the exact same goals.

On Monday morning, Ms Sheinbaum and Mr. Trump spoke on the phone, a call that yielded a faster outcome than the one Mr. Trump held with Mr. Trudeau. Shortly after, Ms. Sheinbaum posted on X that a compromise had been reached.

Addressing reporters later, Ms. Sheinbaum said the discussion had been “very respectful.” Mr. Trump described the call as “very friendly.”

She, too, secured a 30-day reprieve for Mexico in exchange for border and fentanyl measures, most of which, like in the case of Canada, had been part of existing plans.

“We have this month to work, to convince each other that this is the best way forward,” Ms. Sheinbaum said at her regular morning news conference after speaking to President Trump. Suggesting that she might be able hold off the penalties altogether, she said she had told her American counterpart: “We are going to deliver results. Good results for your people, good results for the Mexican people.”

As for Mr. Trudeau, when the 30-day reprieve lapses, he will be in his last week in office.

A shooting at an adult education campus in central Sweden on Tuesday left at least 10 people dead and injured an undisclosed number of others, in what the prime minister called the worst mass shooting in the country’s history.

The suspect was among the dead, the country’s justice minister, Gunnar Strommer, said. But the authorities released few other details, including the person’s identity and a possible motive.

“We do not think there is any terror motive behind this, but it is too early in the investigation to say,” Roberto Eid Forest, the head of the local police, said on Tuesday evening. “We think we have the perpetrator,” he added, “but we are not ruling out anything.”

The shooting occurred in Orebro, a city about 120 miles west of the capital, Stockholm. It came as Sweden, which used to be associated with high living standards, equality and welcoming asylum policies, has been grappling with one of the highest per capita rates of gun violence in the European Union, statistics show.

The gunfire on Tuesday erupted about 12:30 p.m. local time at the Risbergska educational center, which caters to about 2,000 students and offers classes for adults studying for a high school diploma, along with Swedish-language and vocational classes, according to a website run by the Orebro municipality.

Cellphone footage broadcast on local TV stations showed students cowering under desks and chairs, and others running from the building to emergency service vehicles. The authorities said late Tuesday that the number of people injured was still unclear.

“I was eating with colleagues when, all of a sudden, a lot of students came running, saying we have to leave,” the center’s principal, Ingela Back Gustafsson, told Sweden’s public broadcaster, SVT. “When we were out in the schoolyard, I heard a lot of shots nearby. We yelled, ‘Run, run.’ And we ran for our lives.”

The authorities launched a “major operation,” with police cars swarming the campus, armed specials forces officers spilling out of vehicles and officials locking down the campus, several schools in the area and even a restaurant as they searched for the shooter.

Police officers investigated various addresses in the city, the authorities said. After several hours, the police evacuated the center’s classrooms, allowing dozens of students and children to leave.

Mr. Forest said that the shooter most likely had acted alone, was not affiliated with a gang and had not been known to the police. But in a statement, the police also did not rule out the possibility that the shooter might have worked with others.

The shooting sent shock waves across the Scandinavian country.

“We have seen a brutal act of violence,” Prime Minister Ulf Kristersson said in a televised address. “This is the worst mass shooting in Swedish history.”

Mr. Kristersson also said in a statement on social media: “It is a very painful day for all of Sweden. Being locked in a classroom, fearing for your life, is a nightmare that no one should have to experience.”

Shootings are rare in Swedish schools, but the country has seen an increase in violent crime in recent years. Its homicide rate has risen to among the highest in the European Union, the Swedish National Council for Crime Prevention said this year.

While Sweden has strict gun laws, with licenses usually limited to hunting rifles, criminologists have linked a rise in shootings to the illegal drug trade and stockpiles of firearms smuggled in from postwar Balkan countries, Eastern Europe and Turkey. Gangs are also known to groom and recruit children as young as 11 to be contract killers, the police say.

The record for the highest number of shootings was set in 2022, with 391 episodes, police figures show.

In 2022, an 18-year-old student wielding an ax, a knife and a hammer killed two teachers in the southern city of Malmo. In 2015, Sweden was stunned when a 21-year-old man, armed with a sword, killed a teacher and a student at a school in the southwestern part of the country.

The mass shooting on Tuesday left Swedes reeling.

“We haven’t had these kinds of shootings in Sweden before,” Anders Svahn, a teacher at another school in Orebro, said by phone on Tuesday. “One is very touched and affected by this. I know people who work there.”

Last year, teachers and students at Mr. Svahn’s high school, which also offers adult education, practiced a shelter-in-place drill for the first time, he said.

“It’s a risk that has increased, but it’s not something you think about every day,” he added.

Classes at the Risbergska center are unlikely to take place on Wednesday, and it was not clear if other schools in the area would reopen.

Nooshi Dadgostar, the leader of the opposition Left Party, said on social media: “Shocked by the terrible news from Orebro. The violence our country is going through is an abyss we must find our way out of together.”

An international panel of neonatal and pediatric specialists on Tuesday raised grave doubts about the evidence used to convict Lucy Letby, a British nurse who was found guilty in 2023 of murdering seven babies at the hospital where she worked and attempting to murder seven others.

In a dramatic news conference in London, the chairman of the panel, Dr. Shoo Lee, a Canadian neonatologist, said an extensive independent review had found no evidence that Ms. Letby had murdered or attempted to kill any of the infants in her care.

He also highlighted what the 14-member panel determined were errors in medical care at the unit where the deaths occurred, at the Countess of Chester Hospital in northwestern England, in 2015 and 2016, and serious failings in the management of neonatal conditions. Some of the deaths had been preventable, he said.

But, Dr. Lee said, “Our conclusion was there was no medical evidence to support malfeasance causing injury in any of the 17 cases in the trial,” referring to the original charge of harming 17 babies. He added: “In summary, ladies and gentlemen, we did not find any murders.”

The review is significant because it was carried out by some of the most respected and experienced neonatal and pediatric specialists in the world.

The findings raise the most serious questions yet about a case that horrified Britain and led to Ms. Letby being called “the killer nurse” by the news media and vilified as one of the worst serial murderers of children in the country’s modern history. The prosecution told the jury in two trials that she had harmed babies through a macabre range of attacks: injecting them with air, overfeeding them with milk, infusing air into their gastrointestinal tracts and poisoning them with insulin.

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Syria’s new interim leader, meeting on Tuesday with the president of Turkey, thanked him for backing the rebel forces that toppled the Assad dictatorship and said he now sought a deep strategic relationship that would benefit both their countries.

The meeting was President Recep Tayyip Erdogan’s first with Ahmed al-Shara, who led the offensive that toppled President Bashar al-Assad of Syria last month. Both countries have a lot riding on their relationship, and the public comments by the two leaders after they met in the Turkish capital, Ankara, made clear that they are both looking to the future.

Mr. al-Shara, who was appointed interim president by a group of rebel leaders during a closed-door meeting last week, thanked Mr. Erdogan and his people for their support for Syrian refugees and for the Syrian opposition during the war. He said that Syria sought a “deep, strategic relationship in all fields” that would benefit both countries.

This would include developing a “shared strategy to confront security threats in the region,” he said, specifically mentioning northeastern Syria, which is controlled by a Kurdish-led militia that is not under Mr. al-Shara’s authority.

Turkey considers that militia, which is backed by the United States to fight the jihadists of the Islamic State, a terrorist organization because of its ties to Kurdish militants in Turkey and Iraq who have battled the Turkish state.

Mr. Erdogan, too, spoke of unifying all of Syria under the new government and said he appreciated the new authorities’ “strong will to fight terror,” a reference to the Kurdish-led militia.

Turkey shares a long border with Syria, hosts more than three million Syrian refugees and had chilly relations with Mr. al-Assad for years. Mr. Erdogan began speaking of mending ties not long before Mr. al-Assad’s ouster.

Turkey worries that instability in Syria could lead more refugees to flee or prevent those already in Turkey from returning home. Turkey also has military posts in northwestern Syria and directly backs Syrian armed groups near the border.

For Mr. al-Shara, Turkey could provide critical support as he faces the monumental tasks of unifying Syria, reviving its battered economy and transforming a constellation of militias into a national army.

Turkey has been interacting with armed groups that Mr. al-Shara has led since early in the war because they controlled significant territory along Turkey’s southern border, and Turkish officials were among the first to visit him in Damascus after Mr. al-Assad’s fall.

Mr. al-Shara arrived in Ankara on a Turkish state jet and was welcomed on the runway by Turkey’s energy and natural resources minister, Alparslan Bayraktar.

Mr. Erdogan said that Turkey stood ready to help Syria rebuild its infrastructure and that it would work for the lifting of the broad sanctions imposed on the country to punish Mr. al-Assad. The sanctions could impede reconstruction efforts.

Mr. al-Shara concluded his remarks by inviting Mr. Erdogan to visit Syria and the two men warmly gripped hands.

Despite Turkey’s close ties with the new authorities in Damascus, it is struggling to fix its own economy after years of populist spending and persistently high inflation. It would be difficult for it to provide Syria with the financing it needs to restart the economy and begin rebuilding communities that were reduced to rubble during the war.

So Mr. al-Shara has also worked to build ties with the United States, European countries and Gulf Arab leaders.

Last week, Sheikh Tamim bin Hamad Al Thani, the emir of Qatar, became the first head of state to visit Mr. al-Shara in Damascus. And on Monday, Mr. al-Shara met in Saudi Arabia with Crown Prince Mohammed bin Salman, the kingdom’s de facto ruler. To what extent these leaders will help fund the new Syria remains to be seen.

Mr. al-Shara, a former member of Al Qaeda, announced a public break with the group years ago and now expresses more moderate Islamist views. The militia he leads remains classified as a terrorist organization by the United States and other countries.

Safak Timur contributed reporting.