“It is obvious that he was killed by Putin,” said Ukrainian President Volodymyr Zelenskyy, who was visiting Germany as he sought aid for his country as it fights off an invasion by Russia.

“Putin doesn’t care who dies — only for him to hold his position. This is why he must hold onto nothing. Putin must lose everything and be held responsible for his deeds,” Zelenskyy added.

German Chancellor Olaf Scholz, whose country temporarily took in Navalny in 2020 after he was poisoned with a nerve agent, praised the Kremlin critic’s bravery and said his death makes clear “what kind of regime this is.”

“He has probably now paid for this courage with his life,” Scholz said, standing next to Zelenskyy. The German leader said he met Navalny in Berlin during his convalescence.

Navalny, 47, was serving a 19-year prison sentence on extremism charges in a remote penal colony above the Artic Circle at the time of his death. He has been behind bars since he returned from Germany in January 2021, serving time on various charges that he rejected as a politically motivated effort to keep him imprisoned for life.

Navalny was “brutally murdered by the Kremlin,” said Latvian President Edgars Rinkēvičs in a post on X, formerly Twitter. “That’s a fact and that is something one should know about the true nature of Russia’s current regime.”

Navalny’s associates stressed they didn’t have independent confirmation of his death in the reports that came from Russia’s penitentiary officials. His close ally Ivan Zhdanov said authorities “must notify the relatives” within 24 hours “if true.”

“There hasn’t been any notifications,” he said on X, formerly Twitter. “We have no other comments beyond that.”

The outpouring of sympathy for Navalny’s family and outrage at the Kremlin, which in recent years mounted an unprecedented crackdown on dissent, came from all over the world.

“If this is true, then no matter the formal cause the responsibility for the premature death is Vladimir Putin personally, who first gave the green light to the poisoning of Alexei and then put him in prison,” said Mikhail Khodorkovsky, an exiled Russia tycoon turned opposition figure in exile, speaking in an online statement.

Other Russian opposition activists echoed him.

“If it is confirmed, the death of Alexei is a murder. Organized by Putin,” opposition politician Dmitry Gudkov said on social media. “Even if Alexei died of ‘natural’ causes, those were triggered by his poisoning and further torture in prison.”

Former world chess champion-turned-opposition activist Garry Kasparov said “Putin tried and failed to murder Navalny quickly and secretly with poison, and now he has murdered him slowly and publicly in prison.”

“He was killed for exposing Putin and his mafia as the crooks and thieves they are,” Kasparov, who lives abroad, wrote on X.

Pyotr Verzilov, a prominent member of the Russian protest group Pussy Riot, said “Navalny was murdered in prison.” In a post on X, Verzilov added: “We will definitely take revenge and destroy this regime.”

Western officials also blamed Putin and his government.

EU Commission President Ursula von der Leyen said Navalny’s death showed that “Putin fears nothing more than dissent from his own people.”

She called it “a grim reminder of what Putin and his regime are all about,” and added that it should provide added impetus to “unite in our fight to safeguard the freedom and safety of those who dare to stand up against autocracy.”

NATO Secretary-General Jens Stoltenberg said Russia has questions to answer if the reports are true.

“What we have seen is that Russia has become a more and more authoritarian power, that they have used repression against the opposition for many years,” Stoltenberg said.

Navalny, he said, “was in jail, a prisoner, and that makes it extremely important that Russia now answer all the questions that it will be asked about the cause of death.”

White House National Security Adviser Jake Sullivan told NPR that if Navalny’s death is confirmed, “it’s a terrible tragedy and, given the Russian government’s long and sordid history of doing harm to its opponents, it raises real and obvious questions about what happened here.”

U.S. Vice President Kamala Harris, speaking at the Munich Security Conference, called his death, if confirmed, “a further sign of Putin’s brutality” and that “whatever story they tell — let us be clear — Russia is responsible.”

British Foreign Secretary David Cameron, also at the conference, echoed her remarks, saying “Putin’s Russia imprisoned him, trumped up charges against him, poisoned him, sent him to an Arctic penal colony and now he has tragically died. And we should hold Putin accountable for this.”

Russian lawmakers and other officials bristled at the Western outrage.

Sergei Mironov, leader of a pro-Kremlin party, said “Russia’s enemies” benefit from Navalny’s death.

“Of course, health issues could have been the cause of death. But in any case a premature death of a notorious ‘opposition figure’, especially a month before the presidential election, is beneficial first and foremost to Russia’s enemies,” Mironov said in an online statement. “They will use it to the maximum to pressure us from the outside and to rock with situation within the country.”

Russian Foreign Ministry spokeswoman Maria Zakharova said “the immediate reaction of NATO leaders to Navalny’s death in the form of direct accusations against Russia is self-exposing.” The death was still being investigated, but “the West’s conclusions are already ready,” she said.

Russian opposition activists in Europe called for rallies at Russian embassies on Friday and also were planned in Georgia, Israel and Armenia, according to Anastasia Burakova, founder of Kovcheg, a group that helps Russians in exile.