Russia unleashed a furious bombardment aimed at critical Ukrainian infrastructure overnight on Thursday and on Friday amid increasing worries that the American decision to withhold intelligence assistance could leave Ukraine more vulnerable to attacks.

Ukraine’s energy minister, German Galushchenko, said Russian forces launched a “massive missile and drone” assault on power and gas facilities across the country.

The Ukrainian Air Force reported that Russia sent 261 attack vehicles — 67 missiles of various types and 194 drones, some which were outfitted with dummy warheads to confuse and overwhelm air defense crews.

Ukraine shot down or disabled most of the attack drones, the air force said, but only destroyed 35 of the 67 missiles. Ten more missiles did not reach their targets, the air force said, without elaborating.

French Mirage-2000 fighter jets that arrived in Ukraine one month ago joined F-16’s in the skies for the first time, the air force said, helping in the defense.

The bombardment came just days after the United States said it was suspending intelligence sharing with Kyiv, which Ukrainian officials and analysts have said could compromise Ukraine’s ability to detect and defend against Russian bombardments.

American intelligence gathered from a sophisticated satellite network contributes to Ukraine’s early warning system, giving millions of civilians precious minutes to seek shelter and providing air defense teams with vital information they need to try and intercept inbound missiles and drones.

Russia will try and exploit Ukraine’s vulnerability by intensifying drone and missile strikes, warned the Institute for the Study of War, a Washington-based think tank.

The percentage of missiles Ukraine has been able to destroy in large-scale bombardments has fluctuated throughout the war, often in relation to the pace of deliveries of air defense systems from its Western allies.

Ukrainian officials did not comment on the impact the suspension of intelligence sharing played in defending against the latest bombardment.

Russia has been engaged in a relentless campaign to shatter Ukraine’s infrastructure for more than three years, a tactic aimed at degrading services like water and electricity and demoralizing the Ukrainian public.

Having already ravaged the country’s power plants, Moscow has stepped up attacks on oil and gas facilities. Ukraine’s largest national oil and gas company, Naftogaz Group, said the overnight attack was the 17th aimed at its facilities during the course of the war,

“We are doing and will continue to do everything possible to ensure the country has gas,” Roman Chumak, the head of the company, said in a statement. “The process of dealing with the aftermath of the attack and assessing the damage is ongoing.”

The Russian attacks are also aimed at crippling the nation’s industrial capacity, undermining Kyiv’s efforts to scale up its own domestic arms production.

With the U.S. withholding military support, Ukraine’s domestic production takes on added significance. Despite being under constant pressure, Ukrainian arms makers now supply about 40 percent of all the equipment used by soldiers on the front, according to the Ukrainian government.

The Ukrainian government does not comment on successful strikes on military targets.

Maj. Gen. Vadym Skibitskyi, the deputy chief of Ukraine’s military intelligence agency, told Ukrainian media that “one of the priorities” of the Russians will be targeting “our defense industry enterprises, where weapons are manufactured, where we have increased production of many types of weapons, ammunition, unmanned aerial vehicles and systems.”

The Trump administration has been applying increasing pressure on Kyiv at the same time as it aligns itself with the Kremlin.

Ukrainians and many Western analysts have warned that the Trump policy would not lead to peace but only embolden the Kremlin, which says it will stop its invasion only on its own terms. Ukrainians and their allies in Europe believe those terms amount to total Ukrainian capitulation.

“These Trump administration policies are undermining the leverage that the United States needs to get Russian President Vladimir Putin to accept any peace agreement that is in the interests of the United States, Ukraine, and Europe,” the I.S.W. said, echoing a common critique among Ukraine’s European allies.

But in something of a surprise, President Trump said on Friday that he was considering imposing sanctions on Russia, citing the bombardment in a social media post in which he raised the idea.

“Based on the fact that Russia is absolutely ‘pounding’ Ukraine on the battlefield right now, I am strongly considering large scale Banking Sanctions, Sanctions, and Tariffs on Russia until a Cease Fire and FINAL SETTLEMENT AGREEMENT ON PEACE IS REACHED,” he wrote.

Senior U.S. and Ukrainian officials are planning to meet next week in Saudi Arabia to discuss a possible path to bring the war to an end.

In the latest Russian bombardment, the port city of Odessa in southern Ukraine was hit for the fourth night in a row, DTEK, a prominent Ukrainian power company, said in a statement.

In Kharkiv, which is about 25 miles from the Russian border in eastern Ukraine, Mayor Ihor Terekhov said rescue workers were racing to put out flames after an apartment was damaged in strikes that appeared aimed at critical infrastructure.

“Rescuers pulled a woman from the rubble — she is alive and currently being examined by doctors,” he said. “Search and rescue operations are ongoing.”

At least eight people were injured, he said.

Nataliia Novosolova contributed reporting.

After President Trump imposed tariffs on Canada on Tuesday, Prime Minister Justin Trudeau made an extraordinary statement that was largely lost in the fray of the moment.

“The excuse that he’s giving for these tariffs today of fentanyl is completely bogus, completely unjustified, completely false,” Mr. Trudeau told the news media in Ottawa.

“What he wants is to see a total collapse of the Canadian economy, because that’ll make it easier to annex us,” he added.

This is the story of how Mr. Trudeau went from thinking Mr. Trump was joking when he referred to him as “governor” and Canada as “the 51st state” in early December to publicly stating that Canada’s closest ally and neighbor was implementing a strategy of crushing the country in order to take it over.

The February Calls

Mr. Trump and Mr. Trudeau spoke twice on Feb. 3, once in the morning and again in the afternoon, as part of discussions to stave off tariffs on Canadian exports.

But those early February calls were not just about tariffs.

The details of the conversations between the two leaders, and subsequent discussions among top U.S. and Canadian officials, have not been previously fully reported, and were shared with The New York Times on condition of anonymity by four people with firsthand knowledge of their content. They did not want to be publicly identified discussing a sensitive topic.

On those calls, President Trump laid out a long list of grievances he had with the trade relationship between the two countries, including Canada’s protected dairy sector, the difficulty American banks face in doing business in Canada and Canadian consumption taxes that Mr. Trump deems unfair because they make American goods more expensive.

He also brought up something much more fundamental.

He told Mr. Trudeau that he did not believe that the treaty that demarcates the border between the two countries was valid and that he wants to revise the boundary. He offered no further explanation.

The border treaty Mr. Trump referred to was established in 1908 and finalized the international boundary between Canada, then a British dominion, and the United States.

Mr. Trump also mentioned revisiting the sharing of lakes and rivers between the two nations, which is regulated by a number of treaties, a topic he’s expressed interest about in the past.

Canadian officials took Mr. Trump’s comments seriously, not least because he had already publicly said he wanted to bring Canada to its knees. In a news conference on Jan. 7, before being inaugurated, Mr. Trump, responding to a question by a New York Times reporter about whether he was planning to use military force to annex Canada, said he planned to use “economic force.”

The White House did not respond to a request for comment.

During the second Feb. 3 call, Mr. Trudeau secured a one-month postponement of those tariffs.

This week, the U.S. tariffs came into effect without a fresh reprieve on Tuesday. Canada, in return, imposed its own tariffs on U.S. exports, plunging the two nations into a trade war. (On Thursday, Mr. Trump granted Canada a monthlong suspension on most of the tariffs.)

Glimpses of the rupture between Mr. Trump and Mr. Trudeau, and of Mr. Trump’s aggressive plans for Canada, have been becoming apparent over the past few months.

The Toronto Star, a Canadian newspaper, has reported that Mr. Trump mentioned the 1908 border treaty in the early February call and other details from the conversation. And the Financial Times has reported that there are discussions in the White House about removing Canada from a crucial intelligence alliance among five nations, attributing those to a senior Trump adviser.

Doubling Down

But it wasn’t just the president talking about the border and waters with Mr. Trudeau that disturbed the Canadian side.

The persistent social media references to Canada as the 51st state and Mr. Trudeau as its governor had begun to grate both inside the Canadian government and more broadly.

While Mr. Trump’s remarks could all be bluster or a negotiating tactic to pressure Canada into concessions on trade or border security, the Canadian side no longer believes that to be so.

And the realization that the Trump administration was taking a closer and more aggressive look at the relationship, one that tracked with those threats of annexation, sank in during subsequent calls between top Trump officials and Canadian counterparts.

One such call was between Secretary of Commerce Howard Lutnick — who at the time had not yet been confirmed by the Senate — and Canada’s finance minister, Dominic LeBlanc. The two men had been communicating regularly since they had met at Mar-a-Lago, Mr. Trump’s home and club in Florida, during Mr. Trudeau’s visit there in early December.

Mr. Lutnick called Mr. LeBlanc after the leaders had spoken on Feb. 3, and issued a devastating message, according to several people familiar with the call: Mr. Trump, he said, had come to realize that the relationship between the United States and Canada was governed by a slew of agreements and treaties that were easy to abandon.

Mr. Trump was interested in doing just that, Mr. Lutnick said.

He wanted to eject Canada out of an intelligence-sharing group known as the Five Eyes that also includes Britain, Australia and New Zealand.

He wanted to tear up the Great Lakes agreements and conventions between the two nations that lay out how they share and manage Lakes Superior, Huron, Erie and Ontario.

And he is also reviewing military cooperation between the two countries, particularly the North American Aerospace Defense Command.

A spokesperson for Mr. Lutnick did not respond to a request for comment. A spokesperson for Mr. LeBlanc declined to comment.

In subsequent communications between senior Canadian officials and Trump advisers, this list of topics has come up again and again, making it hard for the Canadian government to dismiss them.

The only soothing of nerves has come from Secretary of State Marco Rubio, the four people familiar with the matter said. Mr. Rubio has refrained from delivering threats, and recently dismissed the idea that the United States was looking at scrapping military cooperation.

But Canada’s politicians across the spectrum, and Canadian society at large, are frayed and deeply concerned. Officials do not see the Trump administration’s threats as empty; they see a new normal when it comes to the United States.

On Thursday, at a news conference, a reporter asked Mr. Trudeau: “Your foreign affairs minister yesterday characterized all this as a psychodrama. How would you characterize it?”

“Thursday,” Mr. Trudeau quipped ruefully.

Panama will release 112 migrants who had been deported from the United States last month and were being held in a remote jungle camp, a minister said on Friday, after lawyers and advocates said the conditions violated Panamanian and international laws.

The migrants come from countries that the United States cannot easily return deportees to, often because those nations will not receive them.

Panama was issuing 30-day temporary humanitarian passes to the migrants to give them time to arrange their return to their homelands, or to other countries willing to take them, Panama’s security minister, Frank Ábrego, told reporters on Friday. He said the passes have a possible extension of up to 90 days.

The decision to release the migrants could represent another challenge to President Trump’s efforts to deport millions of migrants from the United States.

In mid-February, when the United States began sending planeloads of people from Asia, Africa and the Middle East to Panama and Costa Rica — and then those countries began locking up the deportees — it appeared that he had enlisted two pliant nations to help with his ambitious deportation plans.

The images of people locked in a hotel in Panama seemed a potentially powerful deterrent for those thinking about migrating to the United States.

But the decision by Panama to release the migrants suggests that it may be harder than the Trump administration had hoped to press other nations into helping carry out mass expulsions.

The decision to release the migrants did not involve the United States and was made solely by Panamanian officials, according to a person familiar with the discussion among those officials, who was not authorized to speak publicly.

The release amounted to offering the migrants a form of temporary protected status, the person said.

While the government would not offer the migrants hotels or other lodging after they left the camp, known as San Vicente, the migrants would be directed to options for shelter and other assistance, including petitioning for asylum in countries other than their own, the person said. He did not provide further details.

The U.S. State Department did not immediately respond to a request for comment.

“It’s hard to outsource immigration policy because other countries have their own constraints,” said Andrew Selee, the president of the Migration Policy Institute, a nonpartisan research organization.

“This was a bid by the Panamanian government to buy some good will with the Trump administration,” he added. “But it was not yet a developed strategy.”

Mr. Ábrego said that of the 299 migrants that had arrived from the United States, 177 had already returned voluntarily to their countries of origin and another 10 were waiting for flights.

The remaining 112, including several children, come from Afghanistan, Iran and other nations and had been held for more than two weeks in a camp about four hours from Panama’s capital. They would be released in the coming days, Panamanian officials said.

People detained in the United States who cannot be easily repatriated present a hurdle for the Trump administration’s plans for deportations.

Migrant families are also a challenge because under U.S. law, the authorities cannot detain families with children for extended periods.

The administration appeared to have found a workaround last month by sending migrants from other parts of the world to countries willing to take them in, like Panama. The country is under enormous pressure to placate Mr. Trump, who has threatened to take over the Panama Canal.

The migrants held in the San Vicente camp were among those flown to Panama in February and locked for several days in a downtown hotel. Those who did not agree to be deported back to their countries, or who could not easily be sent back for logistical reasons, were bused to the remote camp in eastern Panama, at the edge of the Darién Gap.

The decision to release them comes as Panama’s president, José Raúl Mulino, faces growing pressure from human rights groups over the country’s decision to detain the group without charges.

It was also becoming apparent to officials that it was going to be very difficult to deport some of the migrants — as Panama said it was planning to do — because many came from countries that do not have diplomatic relations with the Central American nation.

If the government of Panama had chosen to hold these people until it could deport them, it might have been holding them for months or more.

This month, an international coalition of lawyers filed a lawsuit against the government of Panama before the Inter-American Commission on Human Rights, claiming that the detention of the migrants violated domestic and international laws, such as the American Convention on Human Rights.

In a statement, Álvaro Botero Navarro, one of the attorneys on the case, called the move a “positive step.” But other lawyers in the coalition added that the government has still not offered a solution to their clients, who they say have the right to seek asylum.

Panamanian officials have repeatedly said that two U.N. agencies — the International Organization for Migration and the U.N. refugee agency — were in charge of the group at the camp.

But neither agency has been present on a daily basis at the camp. Instead, it is Panamanian officials who guard the camp, control access and run daily operations inside. The camp is a fenced campus, migrants have not been permitted to leave, and journalists have not been permitted to enter. Most migrants inside have not had access to legal counsel, according to a few migrants inside who still have cellphones.

Mr. Ábrego said in his remarks that the migrants would be able to speak to their lawyers by today or tomorrow.

Jorge Gallo, a spokesman for the I.O.M., said it was present at the camp on Friday, providing translation services and other assistance at the request of the Panamanian government. He said the organization “welcomes the decision” to release the migrants.

A spokesman for Panama’s security ministry, Aurelio Martínez, said the migrants could move freely in the country, but for no more than 90 days.

“After those 90 days if they stay in the country then they would be staying illegally,” he added.

Mohammad Omagh, a 29-year-old Afghan migrant who was deported from California to Panama, said on Friday that he and a group of men were called into an office to sign several forms allowing for their release.

When he asked if he could apply for asylum in Panama, he said the authorities told him that Panama was not accepting any asylum applications and staying long term was not an option.

He and 14 other men, all of them single, signed the documents, he said.

“They told me you can leave the camp and take a bus to Panama City or wherever you want to go, we are not responsible for you anymore,” he said in a telephone interview from the camp. He said he did not have enough money to pay for hotels and meals.

“It feels like Panama just wants to get rid of us and they don’t want to be responsible for us,” Mr. Omagh said.

Traffic was expected to slowly recover at one of France’s busiest train stations on Friday evening after bomb-disposal crews defused an unexploded World War II bomb that had caused travel chaos after it was discovered north of Paris.

The bomb was discovered in the Saint-Denis suburb during overnight work on tracks that lead into the Gare du Nord, a major Parisian transit hub that serves northern France and other parts of Europe, including Britain. Authorities halted all train traffic at the station after the discovery, causing disruptions that rippled across the English Channel.

“This was not a trivial operation,” Philippe Tabarot, France’s transportation minister, told reporters in Paris after the bomb was defused, adding that more than 300 police officers had been deployed to clear and secure a broad perimeter around the device, which weighed more than 1,000 pounds.

The bulky, cylindrical, rock-encrusted bomb was discovered around 3:30 a.m. about a mile and a half from the Gare du Nord, France’s national railway company said in a statement. Workers were landscaping at a bridge renovation site when an earth-moving machine revealed the bomb, which had been buried about six and a half feet underground.

It is about three feet long and includes more than 400 pounds of explosive material, the company said, adding in a travel notice that “extensive earthworks” were necessary to safely defuse it. The police also temporarily closed off sections of a nearby road and a highway.

President Trump has never had much love for the NATO alliance, which he thinks is overdependent on American largess, and in his first term, talked about abandoning the collective defense pact.

In his second term, Mr. Trump and his senior officials have made it clear that the security of Europe is no longer the first priority of the United States, which wants to concentrate resources on its own border and the Indo-Pacific, where China has become a peer rival.

On Thursday, Mr. Trump suggested that the United States might not protect NATO members that he believed were not paying enough for their own defense, calling it “common sense.”

But what would Europeans need to do to replace the enormous American contribution to NATO?

The answer comes down to money, personnel, time and cooperation with Washington, said Ivo Daalder, a former American ambassador to NATO and a coauthor of a recent report from Harvard’s Belfer Center on how to create “a strong European pillar” in the alliance.

The central problem is that NATO was built as an American-dominated alliance, intentionally dependent on American leadership, sophisticated weaponry, intelligence and airlift. The current NATO command structure is essentially owned and operated by the United States, led by Gen. Christopher G. Cavoli.

“The United States is the linchpin of the alliance so we could control our allies and get them to do what we want,” Mr. Daalder said. More practically, the United States military is the skeleton of NATO, and “if you suddenly pull out the skeleton, the body dies.”

Money

Relative to other challenges, money is the easiest part of the European quandary. The question, as ever, is political will and commitment to spending larger sums — and the trade-offs and political costs it will entail.

Prime Minister Donald Tusk of Poland put it simply last week, saying: “500 million Europeans ask 300 million Americans to protect them from 140 million Russians.” What Europe lacks, he said, is “the belief that we are truly a global force.”

Friedrich Merz, who is on course to be the next chancellor of Germany, offered a bold response this week to the new pressures on Europe, proposing to spend nearly 1 trillion euros, or $1.07 trillion, on the military and infrastructure over the next 10 years.

Britain, Belgium, Poland and Denmark have also recently said they would spend more. On Thursday, E.U. leaders agreed to boost military spending outside normal debt limits. But overall, European nations remain far shy of the spending that experts say they will need to replace the American commitment.

Those estimates vary, but could mean a hike of €250 billion a year, or about 1.5 percent of the European Union’s gross domestic product, according to a study from two research institutions, Bruegel and the Kiel Institute for the World Economy.

The study recommends that European nations spend at least 3.5 percent of G.D.P. per year on the military; currently just five of 32 NATO members, including the United States, spend above 3 percent.

The Europeans possess a lot, but also need a lot more sophisticated weaponry, now largely provided by the United States. The biggest gaps are in integrated air and missile defense and long-range precision strike capability, said Ben Hodges, a former commander of the U.S. Army in Europe.

Europe also lacks “strategic enablers,” including transport aircraft, sophisticated drones and satellites — crucial systems for intelligence, surveillance and reconnaissance.

It has the capacity to produce more of its own weapons, he said. But that would require better coordination among nations to invest in the right industries and purchase jointly.

Ideally, Europe should have sufficient stocks of ammunition and missiles to fight a high-intensity war for at least six months, but those are badly depleted from the war in Ukraine.

A study by the International Institute for Strategic Studies found that even fundamentals like the number of combat battalions and in-service battle tanks have remained static or fallen since 2014, despite Russia’s annexation of Crimea.

Political will matters here, too — to overcome bureaucratic constraints and requirements on manufacturers.

The European Investment Bank is prohibited from providing loans to make weapons, though the European Union is rethinking the rule.

And German law requires that weapons makers have direct orders from the government before production can even start. That makes production for potential future sales impossible even if they have excess capacity now.

Personnel

Right now, there are only about 100,000 U.S. troops in Europe — a number that could fit into the University of Michigan’s football stadium — said Mr. Hodges, who used to command them.

Yet it seems almost impossible that the Europeans, even if they increase military spending, could quickly replace the bulk of them, let alone fight on their own for any extended period.

Of the U.S. troops, 20,000 were sent to Europe after Russia invaded Ukraine three years ago, to shore up NATO deterrence. Analysts expect the Trump administration to pull out those troops before too long.

Another 40,000 of the U.S. troops, Mr. Hodges said, are in Europe on expensive rotations, which Mr. Trump is also likely to want to stop.

There are multiple problems for Europe in replacing such numbers.

Only a handful of European nations still have conscription forces. And attracting the right recruits is hard; pay scales and career prospects are better in the civilian world. Even once soldiers are trained, especially in high-tech warfare or “back office” jobs like engineering or mechanics, it is hard to retain them.

Recent suggestions that Europeans put troops into Ukraine to secure a potential peace deal would put extra strain on personnel, potentially for the long term.

NATO is already pressing members to meet requirements for a new force model. Under that agreement, more than 300,000 troops would need to be available within 30 days to reinforce the alliance’s eastern flank against Russia in the event of a crisis.

For now, there are simply not enough soldiers, logistics specialists and intelligence officers to go around.

“European armies are too small to handle even the arms that they’ve got now,” said Jim Townsend, a former U.S. deputy assistant secretary of defense who is now at the Center for a New American Security.

“The British and the Danes, to pick two examples, are good militaries, but they would not be able to sustain intense combat for more than a couple of weeks,” he said. “It doesn’t matter how good you are if there aren’t enough of you.”

Time

The scale of what the Americans now handle for NATO is too big to replace quickly. To buy or produce the necessary equipment and recruit and train the necessary troops will simply take time.

In normal times, it would take a decade for Europe to catch up, said Camille Grand, a former NATO assistant secretary general, who wrote a detailed report about the problem for the European Council on Foreign Relations last year.

Today’s accelerated sense of urgency might help the Europeans do it a little sooner. But critics argue that Europe has waited far too long to respond to clear signaling from Mr. Trump’s first presidency, let alone to his Russia-friendly comments during the campaign.

American officials from both parties have been urging European allies to do more for their own defense for 50 years, and President Emmanuel Macron of France’s warnings in 2019 about fading American commitment to NATO were heard but largely unheeded.

The Europeans are finally trying to address the money problem. But they cannot magically reduce the time needed to make a transition from American domination of NATO in a way that would not damage their security sufficiently to tempt Russia to test the alliance.

Most importantly, it would require that the United States aid the transition and synchronize its withdrawals with the European buildup.

Cooperation

To move from a U.S.-dominated conventional defense of Europe to a European one could be very dangerous without American cooperation.

A sudden American withdrawal would be tremendously tempting for President Vladimir V. Putin of Russia, who wants to undermine NATO. The United States must be willing to wait to withdraw key capabilities until Europeans are ready to take them over, Mr. Daalder said.

Even in Ukraine, with its 900,000 soldiers helping to pin down the Russian army, a European commitment of even 30,000 to 40,000 peacekeeping troops could undercut NATO’s ability to deter Russia from testing the alliance in the Baltics, for example.

That has led some experts to suggest that a European force in Ukraine should be a NATO force, without U.S. troops on the ground, something Mr. Trump has in any case ruled out. But a NATO force, at least, could use existing NATO assets, like surveillance planes and intelligence capabilities, within the NATO command structure.

Others, like Max Bergmann of the Center for Strategic and International Studies, think it’s time to revisit the concept of a European army, which had long been opposed by the United States.

A unified army, he suggests, would go a long way to ending duplication and making spending more efficient. But who would command such an army, and under what political authority, are difficult questions to answer.

A standing European army, he argues, need not replace the United States in each capacity but could be integrated into NATO and be robust enough to do its main job: to deter Russia from invading member states.

After all, he notes, “Europe on paper has nearly 2 million personnel in uniform and spends roughly $338 billion per year on defense, more than enough to deter Russia and enough to make Europe collectively a military power.”

Rome had spent months prepping up for the Roman Catholic Church Jubilee. It built tunnels, opened up squares and scrubbed moldy fountains. Now thousands of pilgrims were flocking from all over the world for the occasion — a year of penance and forgiveness that takes place every quarter century.

The only thing missing was the pope.

For the past three weeks, Pope Francis, leader of the world’s nearly 1.4 billion Catholics, has been in seclusion on the 10th floor of the Gemelli hospital, where he is being treated for pneumonia and other infections. He has missed his regular Wednesday general audiences, where he greets visitors and pilgrims, and his Sunday Angelus prayer, and on Ash Wednesday he entrusted his homily to a cardinal.

A brief audio recording of the pope faintly giving a blessing in Spanish was all the faithful received on Thursday, as they gathered for a rosary for Francis in St. Peter’s square.

“We were hoping we could see him,” said Dinora Ramirez, a pilgrim from Honduras, who prepared to cross St. Peter’s basilica’s holy door as tears filled her eyes. “Our hearts are aching.”

Doctors speak of a “guarded prognosis” for the pope. They have offered mostly terse reports about his condition, which has alternated between crises and stable moments, leaving ample room for conspiracy theories to flourish about his health and his intentions to resign, and even false reports of his death.

But the one undisputed reality is the pope’s prolonged absence.

It is especially notable for a pope who has made a point of being among the people, frequently venturing into crowds, embracing the faithful and engaging in impromptu conversations. And it is even more deeply felt as thousands of pilgrims have been coming to Rome hoping to catch a glimpse of Francis, and as Roman Catholics prepared for Easter celebrations.

On Ash Wednesday, the first day of Lent, about a dozen cardinals in red biretta caps and shoulder capes walked in a procession among olive trees and umbrella pines along Rome’s Aventine Hill, then entered the Santa Sabina basilica for Mass. As the warm afternoon light filtered through the windows, Pope Francis’ homily — prepared, a Vatican official said, before his illness — echoed in the basilica.

But Francis did not deliver it. An Italian cardinal, Angelo De Donatis, read the pope’s words, imposed ashes on the friars’ balding heads and swung the censer as the choir chanted.

“The pope is not here and you can feel it,” said Mario Maurer, 27, a theology student at the Mass. He had come to Rome on a pilgrimage for the Jubilee.

“There is a cardinal who can read the text, and that’s OK,” Mr. Maurer said. “But the pope is a whole other category.”

Standing outside Santa Sabina as he paused his tour of Rome’s infinite churches, Mr. Maurer said the pope’s absence was palpable not only during the Mass but also in the city, of which he is the bishop. “It’s this void that is here, but also in Rome itself,” he said.

In his sermon, Pope Francis offered a message in keeping with his long-established themes, lamenting “the return of old identity ideologies that theorize the exclusion of others, the exploitation of the earth’s resources, violence in all its forms, and war between peoples.”

For some of the faithful who attended, that, at least, was a consolation.

“He made us feel his presence through the homily, which was in the spirit of Pope Francis, about peace, pollution,” said Giuseppina De Palma, 67.

The Vatican official did not rule out that going forward, Francis might hold off preparing texts if he is aware that he is not going to deliver them, saying it might not make sense to do so.

For some Catholics, the pope’s absence at a moment when the global order is under exceptional pressure was particularly disorienting.

“I wish he would tell us more about how to proceed,” said Luz Viviana Flores Maciel, 21, who is originally from Mexico. “The world is upside down, and we are like a nation without a leader.”

For three weeks, the Vatican has also not shared any photos of Francis.

In the past, before the advent of technology and mass media, the physical appearance of popes was much less familiar, even if that did nothing to diminish their authority. But now it is highly unusual for the world to go for weeks without seeing images of the church leader (although there has been a flurry of AI-generated counterfeits circulating on social media).

To try to feel Francis’ presence, some pilgrims have hiked to the Gemelli hospital to pray beneath his windows. Others have chosen not to dwell on his absence.

“Pope Francis would agree that we should focus on the presence of Jesus, rather than anyone of us,” said Jonah Berger, 24, a Dutch Catholic who attended the Ash Wednesday Mass.