Speaking from the White House on Friday afternoon hours after reports of Russian opposition leader Alexei Navalny’s death emerged, President Joe Biden made it clear who he believes bears responsibility.

“Reports of his death, if they’re true — and I have no reasons to believe they’re not, Russian authorities are going to tell their own story — but make no mistake: Putin is responsible for Navalny’s death,” Biden charged. “Putin is responsible. What has happened to Navalny is yet more proof of Putin’s brutality. No one should be fooled.”

Russian authorities said that Navalny, who was serving a 19-year sentence on extremism charges in an Arctic penal colony, died after feeling unwell after a walk. He was 47. Officials in Russia gave no cause for his death, other than to say the matter was under investigation.

When asked explicitly if what happened to Navalny was an assassination, Biden said that while "we don't know exactly what happened," he charged that "there is no doubt that the death of Navalny was a consequence of something that Putin and his thugs did."

Navalny has been behind bars since 2021 after he returned to Russia from Germany, where he was recovering from being poisoned with a nerve agent in 2020. Navalny blamed the poisoning on the Kremlin (he at one point released a video depicting him tricking a Russian intelligence officer into confessing the alleged assassination attempt).

He was arrested upon his return to Moscow and convicted multiple times; he rejected each case as being politically motivated.

Biden offered his "deepest condolences" to Navalny's staff and supporters, who are "going to continue his work despite this loss, despite all of Putin's desperate attempts to stamp out the opposition," as well as his family "who have already sacrificed so much for their family, and a shared dream for a better future for Russia."

"He bravely stood up to the corruption, the violence and all the bad things that the Putin government was doing," Biden said. "In response Putin had been poisoned. He had him arrested, he had him prosecuted for fabricated crimes, he sentenced him to prison. He was held in isolation. Even all that didn't stop him from calling out Putin's lies. Even in prison he was a powerful voice was a truth, which is kind of amazing when you think about it."

Biden said that Navalny "could have lived safely in exile" after the poisoning attempt, but "instead he returned to Russia, returned to Russia, knowing he'd likely be imprisoned, or even killed if he continued his work, but he did it anyway because he believes so deeply in his country, in Russia."

“He was so many things that Putin was not,” Biden later added of Navalny. “He was brave, he was principled, he was dedicated to building a Russia where the rule of law existed and where it applied to everybody.”

During his remarks Friday, Biden was asked about his comments from three years ago after his June 2021 summit with Putin; the president said at the time that he made clear to the Russian leader that if Navalny dies, "the consequences of that would be devastating to Russia."

"That was three years ago," Biden said Friday, emphasizing the actions the U.S. and its allies have taken against Russia since its invasion of Ukraine began in February 2022. "In the meantime, they faced a hell of a lot of consequences. They've lost lost and/or had wounded over 350,000 Russian soldiers, they made it into a position where they've been subjected to great sanctions across the board and we're contemplating what else can be done."

When asked about the possibility of further sanctions, Biden replied: "We're looking at a whole number of options."

Biden also referenced the war in Ukraine, urging Congress to act on the long-stalled foreign aid package which would aid the country in repelling Russia's invasion, while also taking aim at his likely opponent in November's election, former President Donald Trump, who recently sparked alarm across the world when he said Moscow should be able to do “whatever the hell they want” to NATO members who don't meet their defense spending targets. Biden roundly condemned those comments and his reelection campaign launched an ad blitz in battleground states highlighting Trump's remarks.

"No one should be fooled, not in Russia, not at home, not anywhere in the world," Biden said. "Putin does not only target his citizens of other countries, as we've seen in what's going on in Ukraine right now, he also inflicts terrible crimes on his own people."

"As I said before, and I mean this in a literal sense, history is watching," Biden said. "History is watching the House of Representatives. The failure to support Ukraine at this critical moment will never be forgotten. It's gonna go down in the pages of history, it really is. It's consequential, and the clock is ticking. And this has to happen. We have to help now.

"We have to realize what we're dealing with Putin," he continued. "All of us should reject the dangerous statement made by the previous president that invited Russia to invade our NATO allies if they weren't paying up. He said if an ally did not pay their dues, he'd encourage Russia to 'do whatever the hell they want.'"

Biden then paused and said: "I guess I should clear my mind a little bit not say what I'm really thinking."

"Let me be clear: This is an outrageous thing for a president to say," Biden said. "I can't fathom ... presidents from [Harry] Truman on, they're rolling over their graves hearing this. As long as I'm president, America stands by our sacred commitment to our NATO allies, as they have stood by their commitments to us repeatedly. Putin and the whole world should know if any adversary were to attack us our NATO allies would back us, and if Putin were to attacking NATO allies, the United States will defend every inch of NATO territory. Now's the time for even greater unity among our NATO allies to stand up to the threat that Putin's Russia poses."

"God bless Alexei Navalny," Biden concluded. "His courage will not be forgotten."