President Biden on Friday blamed Russian President Vladimir Putin for the death of Russian opposition leader Alexei Navalny.

Why it matters: Biden has said Russia would face "devastating" consequences if Navalny died in prison. On Friday, he said his administration was "looking at options" after being asked about additional sanctions against Moscow over Navalny's death.

• "Make no mistake, Putin is responsible for Navalny's death. Putin is responsible," Biden said.

Catch up fast: Russia's prison service said on Friday Navalny suddenly lost consciousness and died while walking in the Arctic penal colony where he had been held since December.

• Navalny was the leading critic of President Vladimir Putin. He organized the most effective political movement against the Kremlin centered around a crusade for free and fair elections and against high-level political and financial corruption.
• He had been in prison since 2021 on charges denounced internationally as being fabricated for political retaliation. He had entered Russia's brutal penal system shortly after surviving a Kremlin-linked assassination attempt in 2020.
• Navalny's representatives have said they have had no way to confirm if or how he died, and that if he did die, they believe he was killed.

What they're saying: Biden said Navalny's death is more evidence of Putin's brutality.

• "Putin not only targets the citizens of other countries, as we see with what's going on in Ukraine right now, he also inflicts terrible crimes on his own people."
• Biden also commended Navalny's return to Russia after the assassination attempt, saying the opposition leader did so "because he believed so deeply in his country."
• "People in Russia and across the world are mourning Navalny today because he was so many things that Putin is not," Biden said. "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."

The big picture: Biden again urged lawmakers to approve of additional aid for Ukraine's defense against the Russian invasion that Navalny had opposed.

• "History is watching the House of Representatives," Biden said. "Failure to support Ukraine at this critical moment will never be forgotten. It's going to go down in the pages of history."
• Biden also denounced former President Trump's recent threat to "encourage" Russia to attack NATO allies not meeting certain defense obligations.
• "Let me be clear, this is an outrageous thing for a president to say. I can't fathom. From Truman on they're rolling in their graves hearing this," he said before declaring that the U.S. will defend "every inch" of NATO territory.

Go deeper: Navalny's death electrifies Capitol Hill debate over Ukraine

Editor's note: This story was updated with additional details.