Russia’s full-scale invasion of Ukraine three years ago convinced Europe’s leaders that they needed to spend more money on defense. On Monday, leaders from across the European Union and Britain will meet in Brussels to debate a vexing question: how to pay for it.

It is a concern made more acute by President Trump’s return to the White House

The United States is the largest military funder of Ukraine’s war effort, but Mr. Trump has suggested he will rapidly withdraw U.S. financial and military support and leave it to the Europeans. He has also insisted that NATO nations ramp up defense outlays to 5 percent of their annual economic output, a drastic increase from the 3 percent or 3.5 percent NATO plans to make its goal at its next summit meeting this summer. The United States itself spends only about 3.4 percent of gross domestic product on defense.

And security is only one of the arenas in which the Trump administration is striking a more confrontational stance. Mr. Trump pledged on Sunday night to slap new tariffs on European trading partners “pretty soon.” That is intensifying a sense in Europe that it needs to be able to fend more for itself in a world where the United States is a less reliable partner.

With the war in Ukraine, the European Union, which was founded on free trade and termed itself a “peace project,” has become more committed to deterrence and defense. It is now scrambling to expand its defense industries and make spending more efficient and collaborative. Prime Minister Keir Starmer of Britain will attend Monday’s gathering, the first time since Britain left the European Union that a British leader has met with the 27 leaders of the bloc in Brussels.

Part of the debate will be whether the European Union will be able to raise more money to pay for defense through common debt, as it did to fight Covid.

But the issue is thorny: Such joint fund-raising might impede the efforts of member countries to meet the individual demands that the NATO alliance is already making of them in terms of raising military budgets. Of the 27 E.U. countries that will meet in the closed-door session on Monday, 23 are members of NATO.

NATO’s supreme allied commander in Europe, Gen. Christopher G. Cavoli, has already set capability targets for the first time since the Cold War. The American general has given NATO member countries specific requirements for equipment and force levels, as well as instructions on how to respond in case of a Russian invasion.

There is consensus among officials and analysts that Europe lacks crucial elements of defense like integrated air and missile defense, long-range precision artillery and missiles, satellites, and air-to-air refueling tankers that only the United States currently provides. Replacing those systems would take Europe at least five or perhaps 10 years, the analysts say.

European nations also want to reduce duplication. Ukraine, for example, has been sent at least 17 different kinds of howitzers, not all of which use the same type of shell.

As Russia threatens from the East and Mr. Trump’s support wavers from the West, Europe’s leaders agree that they need a plan to both coordinate and expand their military resources. But diverging national interests and competing budget priorities mean that reshaping European defense will be difficult, expensive and lengthy.

And important countries on the eastern flank, like Poland and the Baltic nations, want to do whatever they can to keep the United States engaged in NATO and the defense of Europe.

The summit Monday is a first step. The E.U. leaders will discuss military financing and joint procurement, and be joined by Mr. Starmer and by Mark Rutte, the NATO secretary general. The goal is to hash out priorities, which will inform the continent’s top diplomat, Kaja Kallas, and its new defense commissioner, Andrius Kubilius, as they work to draw up a more concrete plan, especially for weapons production.

The meeting also has symbolic importance, defense analysts said, as a demonstration that Europe is taking seriously a long-term threat from Russia and the need to reduce its military dependency on the United States.

“This is critical for Europeans,” said Alexandra de Hoop Scheffer, acting president of the German Marshall Fund, a think tank. “They don’t have a choice, because war is taking place on their own continent.”

Deterring Russia, which wants to split the United States from NATO and divide both the alliance and the European Union, is “a generational struggle,” she said. “But our political leaders have failed to explain to a younger generation why the alliance is important and why it’s important for Ukraine to win this war,” she said.

Europe’s relationship with Washington is also on Monday’s agenda, including how to cope with Mr. Trump’s demands. Officials expect the discussion to address his insistence that he wants to acquire Greenland. The island is an autonomous territory of Denmark, both an E.U. member state and a NATO ally. Danish and Greenlandic leaders say the territory is not for sale and will not be handed over to the United States.

The Greenland issue underscores just how drastically Washington’s relationship to Europe may be changing, as Mr. Trump seems more willing to put economic and military pressure on U.S. allies than on its adversaries.

But there is still a degree of shock in Europe.

“Nobody takes it seriously, or literally,” said Jacob Funk Kirkegaard, a senior fellow at Bruegel, a think tank in Brussels, who studies European economies and trans-Atlantic relations. “Nobody wants to do so, because it would require rethinking the world as we know it.”

While leaders like Mr. Rutte have emphasized that the continent cannot realistically go it alone without the United States, the goal is to be more self-sufficient.

E.U. nations have increased military outlays in recent years. They spent an estimated $340 billion on defense in 2024, a 30 percent increase compared with 2021. At least 23 of NATO’s 32 members now spend 2 percent or more of their gross domestic product on defense, in line with NATO goals. Mr. Rutte has made it clear that 2 percent is a floor, not a ceiling, and that a new, higher standard will be set this year.

With President Vladimir V. Putin of Russia busy with Ukraine and his military battered, European and NATO officials believe there is a window of perhaps three to seven years before Mr. Putin might be tempted to test the NATO alliance.

Finding a fix that boosts and coordinates European defense outlays will not be easy.

“The logic tells us that you need to have joint procurement,” said Janis Emmanouilidis, director of studies at the European Policy Center. But there are barriers, including a lack of trust between nations and conflicting national self-interest. “It is protecting national industry, it is protecting the sovereign right to make decisions,” he said.

When it comes to joint procurement, there is also the issue of how to finance it. Joint funding programs are clearly on the agenda, but exactly what that could look like varies.

It could mean a collective pot of money like Europe raised during the 2020 coronavirus pandemic. Funding could also come from a vehicle supported by the European Investment Bank, which is the lending arm of the European Union, or from a group of nations outside the structures of the bloc.

In a joint letter last week, 19 European countries said the bank “should continue exploring further ways to take an even stronger role in providing investment funding and leveraging private funding for the security and defense sector.”

The letter suggested a serious discussion of “specific and earmarked debt issuance” for defense projects. For now, key member states like Germany and the Netherlands reject the idea of collective borrowing for defense, and the EIB is prohibited from making loans for strictly military uses.

Any serious European defense would have to include Britain, a nuclear power and member of the United Nations Security Council, the main reason Mr. Starmer has been invited to attend. He has himself emphasized security cooperation with the European Union as a way to bring post-Brexit Britain closer to the bloc.

Mark Landler contributed reporting from London.

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.

If the second Trump term marks the sunset of Pax Americana, analysts say China will almost certainly use the opportunity to try to reshape the world in its favor. Beijing, which has long accused Washington of using its dominance to contain China’s rise, has tried to drive a wedge between the United States and its allies, including the European Union, Japan and Australia.

“The Chinese are well aware of the damage Trump has done and is doing to U.S. credibility and influence globally. In fact, it is unfolding faster than even Beijing expected,” said Evan S. Medeiros, a professor of Asian studies at Georgetown University who served as an Asia adviser to President Barack Obama.

Mr. Trump’s threats to take the Panama Canal and Greenland, as well as to annex Canada as America’s 51st state could normalize a world order in which might makes right. That is an approach that is familiar to Beijing, even if Chinese officials rhetorically maintain that it will never seek hegemony or expansion.

If the United States strong-arms Panama over its crucial waterway, or forces Denmark to give up the resource-rich territory of Greenland, it sends a signal to China that when it comes to its own claims to the self-governing island of Taiwan and much of the South China Sea, coercion trumps cooperation.

“China was certainly never going to give up Taiwan or the South China Sea, but with President Trump doing what he’s doing, China is even more determined to safeguard its interests there, that’s for sure,” said Henry Huiyao Wang, president of the Center for China and Globalization in Beijing.

Mr. Wang said China has been encouraged by the first two weeks of the new administration despite the tariffs and appointment of hawkish advisers such as Secretary of State Marco Rubio and Michael Waltz, the national security adviser.

Rather than coming out aggressively to confront China, Mr. Trump has presented himself as someone willing to negotiate and potentially cut a deal with Xi Jinping, China’s leader. Mr. Trump has floated the idea of tying tariffs to the fate of TikTok, which he has said should be half-owned by an American company.

Another potential area for deal making is Ukraine. Mr. Trump has said China should help end Russia’s war in the Eastern European country. China, as Russia’s biggest provider of economic and material support, could conceivably pressure President Vladimir V. Putin to come to the negotiation table.

“Trump wants China’s help to end the war in Ukraine,” Mr. Wang said. “China is one of the best partners for him to do that.”

But with so many competing interests, cooperation would be difficult. China has avoided criticizing Russia’s invasion of Ukraine, for example, taking the position that Russia has a right to protect its national security. Ukraine will not accept China as a peace broker because of China’s pro-Russian position, said Shi Yinhong, an international relations professor at Renmin University in Beijing. Mr. Putin, on the other hand, will not want to look subordinate to China, he said, while Mr. Trump has “no real stomach” to see China lauded for playing a significant role.

On the issue of tariffs, Beijing has to decide if it can afford to escalate a trade war with the United States. On Sunday, it vowed to respond to Mr. Trump’s tariffs by filing a case with the World Trade Organization and with countermeasures to be specified later.

Beijing could hit back with tariffs. A more drastic approach would be for China to engage in “supply chain warfare”: halting shipments to the United States of materials and equipment critical to U.S. industry. In early December, China stopped the export to the United States of minerals like antimony and gallium, which are needed to manufacture some semiconductors.

The risk to China is that a trade war would be more damaging to itself than it would be for the United States. Exports, and the construction of factories to make them, are among the few strengths now in China’s economy. As a result, China’s trade surplus — the amount by which its exports exceeded imports — reached almost $1 trillion last year.

China has also not yet said how it will respond to a potentially farther-reaching provision in the fine print of Mr. Trump’s executive order on Saturday: the elimination of duty-free handling for packages worth up to $800 per day for each American. Factories all over China have shifted in recent years to e-commerce shipments directly to American homes, so as to bypass the many tariffs collected on clothing and other goods that are imported and sold through American stores.

In the race for global influence, some argue that the Trump administration’s move to freeze most foreign aid, which has disrupted aid programs around the world, has already benefited China.

In regions like Southeast Asia, where attitudes toward the United States have hardened because of Washington’s support for Israel in the Gaza war, the halt in funding has raised questions about American reliability.

“China needs to do nothing in the meantime, and yet, somehow, net-net, look like the good guy in all of this,” said Jeremy Chan, a senior analyst on China at the Eurasia Group.

Senator Lindsey Graham, Republican of South Carolina, defended the importance of soft power to America’s standing.

“If you don’t get involved in the world and you don’t have programs in Africa, where China is trying to buy the whole continent, we’re making a mistake,” he said last month.

Through nearly 16 months of war in Gaza, politicians and analysts debated competing proposals for the territory’s postwar governance, but no clear direction emerged while the fighting continued.

Now, as a fragile cease-fire holds and as Israel and Hamas prepare for negotiations to extend the truce, four rival models for Gaza’s future have begun to take shape.

Hamas, weakened but unbowed, still controls most of the territory and is trying to entrench that authority. Under the terms of the cease-fire, Israel is meant to withdraw gradually from Gaza, but its troops still occupy key parts of it. Right-wing Israeli leaders want their forces to expand that control, even if it means restarting the war.

A group of foreign security contractors offers another model. At Israel’s invitation, they are running a checkpoint on a crucial thoroughfare in northern Gaza, screening vehicles for weapons. Some Israeli officials say that activity could develop into international stewardship of a much wider area, involving Arab states instead of private contractors.

And in the south, representatives of the Palestinian Authority began over the weekend to staff a border crossing with Egypt, working with European security officials. The authority, which lost control of Gaza to Hamas in 2007, hopes that it could, in time, replicate those efforts across the entire territory.

For now, it’s unclear which template will emerge as the dominant model. The outcome will likely depend in large part on President Trump, who is set to discuss Gaza’s future on Tuesday in Washington with Prime Minister Benjamin Netanyahu of Israel. And Saudi Arabia could tilt the scales if it agrees for the first time to forge formal ties with Israel — in exchange for a particular governance structure in Gaza.

Here’s what the models entail and how likely they are to succeed.

Hamas rule

When releasing hostages in recent weeks, Hamas has made a point of showing that it remains the dominant Palestinian force on the ground. Hundreds of masked Hamas militants have assembled at each release point, projecting the sense that the group, though battered by 16 months of war, is still in charge.

Hamas security officials have also re-emerged to assert a semblance of order across the territory, stopping and screening vehicles and trying to defuse unexploded ordnance. Municipal officials have also started shifting rubble.

For most Israelis, Hamas’s long-term presence is unpalatable. Some might accept it if Hamas agreed to release all the remaining hostages held in Gaza. Others, particularly on the Israeli right, want to resume the war, even if it costs the lives of some of those captives, to force Hamas out.

If Hamas does stay in power, it will be hard for the group to rebuild Gaza without foreign support. Because many foreign donors will most likely be wary of helping unless Hamas steps down, it is possible that the group might willingly cede power to an alternative Palestinian leadership, instead of continuing to preside over an ungovernable wasteland. In talks mediated by Egypt, Hamas’s envoys have said they could hand over administrative responsibilities to a committee of Palestinian technocrats, but it’s unlikely that the group would willingly disband its armed wing even if it stopped running Gaza’s civilian affairs.

Israeli occupation

When the cease-fire began last month, Israel retained control of a buffer zone along Gaza’s borders that is several hundred yards wide. To end the war and secure the release of all the hostages in Gaza, Israel eventually needs to evacuate this territory. But that is unthinkable to important members of Mr. Netanyahu’s coalition, meaning that he may extend Israel’s occupation, or even expand it, to avoid the collapse of his government.

To do that, however, Mr. Netanyahu would probably need the support of the Trump administration, which has signaled that it wants to see the cease-fire extended to allow for the release of every hostage. Returning to war would also scupper any short-term chance of a deal between Israel and Saudi Arabia — a major international achievement that Mr. Netanyahu has long coveted.

An international force

When Israeli troops withdrew last week from much of the Netzarim Corridor, a strategic area that connects northern and southern Gaza, they allowed a cohort of foreign security contractors to fill the void. Led by Egyptian security guards, the contractors screen northbound traffic for weapons, hoping to slow Hamas’s efforts to rearm its militants in northern Gaza. Two U.S. companies are involved in the process, but it is unclear what role they play on the ground.

For now, the process is a small-scale trial that lacks the formal involvement of Arab countries other than Egypt and Qatar, the two states mediating between Israel and Hamas. But some Israeli officials say that it could be expanded — both in terms of geography and responsibility — to encompass administrative roles across a wider area, backed publicly and financially by leading Arab states like Saudi Arabia and the United Arab Emirates.

Neither is likely to seek a formal role without the blessing of the Palestinian Authority.

The authority, which Hamas forced from Gaza in 2007, still runs part of the West Bank and is considered the only serious Palestinian alternative to Hamas. But Israeli leaders see the authority as corrupt and incompetent and have dismissed the idea of giving it a major role in Gaza, at least for now. The Israeli right also opposes empowering the authority, lest it emerge as a credible state-in-waiting.

The Palestinian Authority

That said, the authority’s representatives quietly began working in another part of Gaza over the weekend, suggesting that parts of the Israeli leadership may in practice be more flexible about the authority’s involvement.

Israel allowed officials from both the European Union and the Palestinian Authority to restart operations at the Rafah crossing — a checkpoint on the border between Gaza and Egypt. The crossing had been closed since Israel invaded the Rafah area last May.

Publicly, the Israeli government downplayed the authority’s involvement at the checkpoint, partly to avoid angering members of Mr. Netanyahu’s coalition.

But the operations at Rafah have fueled speculation that Mr. Netanyahu, under pressure from Mr. Trump and Arab leaders in the Gulf, might grudgingly tolerate a wider role for the authority, perhaps in partnership with foreign peacekeepers or contractors.

A French court convicted the director Christophe Ruggia on Monday of sexually assaulting the actress Adèle Haenel when she was a minor, handing him a four-year sentence — two years under house arrest and the rest suspended.

It was the first major case to examine an accusation of sexual misconduct in French cinema since the #MeToo movement, which emerged in 2017 and was met with a severe backlash in France.

Mr. Ruggia stood at attention as the judges explained the guilty verdict.

“You took advantage of the influence you had on the young actress Adèle Haenel,” the head judge, Gilles Fonrouge, said.

Ms. Haenel did not show any clear emotion when the verdict — which also ordered Mr. Ruggia to pay 50,000 euros, or about $51,300, in damages — was read out. When she left the Paris courthouse, women gathered outside applauded. A lawyer for Mr. Ruggia said that his client planned to appeal.

Mr. Ruggia cast Ms. Haenel in his 2002 film “The Devils,” about a relationship bordering on incest, when she was 12 and he was 36. After the filming finished, she continued to visit him regularly on Saturdays over three years at his apartment, where, she says, he touched her inappropriately and sexually harassed her.

When Ms. Haenel first revealed such accusations publicly in 2019, she was the first major French actress to speak out about her personal story of abuse since the #MeToo movement emerged. She was a rising star, praised for fierce yet sensitive performances that had earned her two Césars, the French equivalent of the Oscars.

Mr. Ruggia was a relatively unknown director, but in the insular world of French cinema, he had a prominent role in the French directors’ association and had a reputation for making films about social justice and for defending migrants and human rights.

The case stirred huge interest in the country. The courtroom was packed with Ms. Haenel’s supporters over a two-day trial in December.

During those two days, two conflicting versions of the past were presented. Ms. Haenel depicted the regular Saturday sessions in Mr. Ruggia’s Paris apartment, where he was meant to teach her the classics of French cinema, as a ruse to sexually assault her.

Mimicking his voice, she recounted how he would caress her thighs, kiss her on the neck while breathing heavily, put his hands under her T-shirt to touch her breasts and her belly, and under her pants to reach the edge of her intimate parts. She broke ties with him when she was 15 and, for years afterward, described experiencing shame and depression.

She said she was speaking in court to defend her former 12-year-old self and other child victims who were hushed into silence, calling it the “most important thing I’ve done in my life — trying to break the loneliness of children.”

“It makes you want to die, in fact, when no one speaks,” said Ms. Haenel, now 35, who often writhed with anger in the courtroom, her face overcome by tics and her feet banging on the floor.

“Shut up!” she screamed at the director at one point, rushing out of the courtroom.

Mr. Ruggia discounted Ms. Haenel’s account as “pure lies.” He said he had formed a deep bond with the young actress and her co-star, Vincent Rottiers, that extended long after filming. He acknowledged having kissed her on the head and grabbing her, but said it had been in a fatherly manner.

“These were affectionate gestures,” he said in court. Only on one occasion, he said, did her T-shirt roll up as she was bouncing around, exposing her chest. He said he had lowered it and asked her to sit on the armchair from then on.

Although he talked about her overpowering sexuality, and he wrote letters to her stating that his heart was broken after she cut ties with him, Mr. Ruggia said he had never been in love with Ms. Haenel.

“For me, Adèle was a kid, a preadolescent,” he said.

Mr. Ruggia argued that Ms. Haenel had been influenced by another director, with whom she later had a romantic relationship, and that she had been pushed to recast their own platonic relationship as inappropriate and grooming.

“I think she was radicalized,” he said, adding: “There needed to be a #MeToo in France, and it had to fall on me.”

Since the publication in 2019 of Ms. Haenel’s story in an extensively researched article in Mediapart, a French investigative site, Mr. Ruggia has been cast out from cinema. He has moved to Brittany in northwestern France to care for his mother and lives off welfare. He said during the court proceedings that he had been waiting years for the trial, “to see if I’m going to get my life back, if I’m going to be able to make films again or not.”

Since her disclosure, Ms. Haenel has also stopped working in cinema. She later explained in a public letter that she believed the industry protected sexual abusers and preferred that victims “disappear and die in silence.”

“I am canceling you from my world,” she wrote.

The trial’s subtext was how the justice system in France deals with perpetrators of sexual assault and their victims. Ms. Haenel initially told her story to a French investigative journalist and said she did not trust the justice system.

The judges asked Ms. Haenel repeatedly why she did not trust the justice system. The prosecutor, noting the packed courtroom, said in her closing statement: “Justice must also fight silence.”

A car bomb killed 15 agricultural workers in northern Syria on Monday, the country’s civil defense force said, as ongoing violence threatens to undermine the new government’s push for stability.

There were no immediate claims of responsibility for the explosion, which took place in the city of Manbij, about 20 miles from the border with Turkey. Manbij has been a focal point of violence between armed groups, one backed by the United States and the other by Turkey. The blast on Monday was one of the deadliest such attacks since the fall of Bashar al-Assad in December.

The Turkish-backed fighters wrested control of the city in December from Kurdish-led forces, who are supported by the United States, and there has since been a spate of car bombings, according to the White Helmets, the Syrian civil defense force.

The agricultural workers were being transported in the back of a truck when a car bomb exploded alongside them on the outskirts of the city, which lies about 55 miles northeast of Aleppo, the White Helmets said in a statement.

Most of the dead were women. At least 15 other people were wounded, and the death toll was expected to rise, the force said.

Footage from the aftermath showed the charred and mangled remnants of a vehicle, and the truck carrying the workers was pierced with shrapnel.

The continued violence underscored the challenges faced by Syria’s new interim president, Ahmed al-Shara, who is attempting to navigate a critical juncture in the country’s history.

Mr. al-Shara, who was appointed last week, has pledged to create an inclusive transitional government. To that end, the new authorities have announced the dissolution of all armed factions in the rebel coalition that toppled Mr. Assad, the country’s longtime dictator.

It remains unclear, however, whether armed groups that have so far refused to give up their weapons — including the Kurdish-led forces who control most of northeastern Syria — will eventually accept that mandate.

Unifying Syria’s complex web of armed groups under a single umbrella, experts say, is among the most pressing challenges facing the new government.

A prominent pro-Russia separatist figure from Ukraine was killed after a bomb exploded on Monday inside a gated residence in Moscow, Russian news media said, in what appears to be another attack targeting opponents of Kyiv.

The figure, Armen Sarkisyan, the founder of a battalion fighting in eastern Ukraine, was pronounced dead in a Moscow hospital, Russian news media said, citing the country’s Investigative Committee, which typically handles high-profile crimes.

The Investigative Committee said earlier in a statement that four people had been taken to a hospital with injuries after a bomb exploded at the Scarlet Sails apartment complex. It said one person had been killed in the explosion.

The Russian media reports said that Mr. Sarkisyan had been taken to the hospital with injuries and had died there, and that his bodyguard had died at the scene.

The agency did not name any suspects. It was also not immediately clear if Mr. Sarkisyan had been a resident of the complex.

Ukrainian officials have not yet commented on the blast.

The explosion inside a building in an upscale neighborhood appeared to be another significant attack in Moscow, where a Russian general was killed in December by a bomb planted on a scooter in an assassination Ukraine claimed.

The general, Igor Kirillov, was in charge of the Russian military’s nuclear and chemical weapons protection forces. His assistant also died in the attack.

Mr. Sarkisyan was wanted in Ukraine on accusations of plotting killings and hiring thugs to harass antigovernment activists during protests in Kyiv, the Ukrainian capital, in 2014.

He later supported Russia’s invasion of eastern Ukraine in 2014 and most recently founded a battalion fighting alongside Russian forces in Ukraine.

Ivan Prikhodko, the mayor of the Russian-controlled town of Horlivka in eastern Ukraine, where Mr. Sarkisyan was originally from, referred in a Telegram post to the leader’s death, without providing details. He hailed Mr. Sarkisyan’s Arbat battalion for playing a “crucial role in ensuring security” in areas of Ukraine’s Donetsk region that Russia had captured.

Footage posted by Tass, a state-owned news agency, and other Russian media outlets from the scene of the explosion showed the glass doors of the entryway mangled and smashed.

Russian officials did not immediately say how an explosive was planted and detonated.

Dmitri S. Peskov, a Kremlin spokesman, on Monday had no comment on the blast and said that an official inquiry was underway.

More than a week after it began, a standoff between Ukraine’s defense minister and the official overseeing weapons procurement remains unresolved and is beginning to disrupt arms contracts, Ukrainian defense companies say.

Ukraine’s arms industry trade group has said that more than 80 defense companies, accounting for about a third of last year’s supplies to the army, “are unable to receive payment for completed orders and sign new contracts.” In one such case, a contract to produce 155-millimeter artillery rounds, a caliber used in many field guns, has been put on hold, the producer of the ammunition said.

The standoff is unlikely to have an immediate effect on arms supplies to Ukrainian troops, the companies said, as current deliveries are drawn from previous contracts. But if it persists, it could jeopardize supplies in the months ahead at a critical time for the Ukrainian Army, which is already struggling to contain Russia’s advance on the battlefield.

At the root of the issue is a tense showdown over the leadership of Ukraine’s defense procurement agency, which had a budget of over $7 billion last year. The defense minister, Rustem Umerov, recently dismissed the agency’s director, Maryna Bezrukova, citing “poor procurement planning” and delayed supplies to the front line, and appointed an acting head.

Ms. Bezrukova has denied the claims of mismanagement and said her dismissal was illegal, because her contract was extended by the agency’s supervisory board. She said on Monday that she would not resign.

The standoff has escalated to the point where both Ms. Bezrukova and the new acting head, Arsen Zhumadilov, have been working from the agency’s headquarters in recent days, including Monday, leaving international partners and defense companies confused about who was responsible for signing contracts.

“The normal day-to-day work of the defense procurement agency is just blocked,” Serhiy Honcharov, head of the National Association of Ukrainian Defense Industries, said in an interview. “Who is actually in charge? No one knows. In this chaos, it’s impossible to sign contracts.”

Serhiy Bulavko, the head of the procurement control department at the defense ministry, told reporters on Friday that there were “no disruptions in weapons supplies” as of now and that “contracting is underway.”

The tumult in Ukraine’s defense sector also risks derailing Kyiv’s efforts to convince its allies, especially President Trump, to maintain support for its fight against Russia. A key part of these efforts was a new mechanism to fund Ukrainian weapon production with Western money through the agency, as an alternative to direct arms supplies.

Last year, half a billion dollars’ worth of weapons were produced through this mechanism. Kyiv aims to double that amount this year.

The agency was established last year in an effort to curb corruption in the procurement process — a move that was applauded by Ukraine’s Western partners. It buys weapons from both foreign and domestic producers.

Olha Stefanishyna, Ukraine’s minister for European integration and justice, complained last week that the standoff was sending the wrong message to Kyiv’s partners. She told the Ukrainian media outlet Suspilne that NATO members had raised questions about the issue in private meetings. “Such aggressive public communication does not help Ukraine, inside and outside,” she said.

Mr. Umerov sought to dismiss Ms. Bezrukova by declining to extend her contract as head of the agency. The move has sparked some calls for his resignation. But he appears unlikely to step down after President Volodymyr Zelensky voiced support for him in an interview with The Associated Press released Sunday.

“The defense minister has the right to do everything necessary to prevent any delays in supplies,” Mr. Zelensky said.

Vladyslav Belbas, the head of Ukrainian Armor Design and Manufacturing Co., a private Ukrainian arms company, said a contract to produce 155-millimeter artillery rounds that was slated to be signed by late January had been put on hold because of the dispute. Ms. Bezrukova confirmed that the contract had not been signed.

“That affects our production capabilities. Because if we don’t know what’s happening, how can I scale the production or how can I least plan for the production?” Mr. Belbas said in a phone interview.