Alexey Navalny
Alexey Navalny AFP

US President Joe Biden is "considering additional sanctions" on Moscow after the death of Russian opposition leader Alexei Navalny in an Arctic prison, he said Monday.

"We already have sanctions, but we are considering additional sanctions, yes," said Biden, who has already directly blamed Russian President Vladimir Putin and his "thugs" for Navalny's death last week, speaking to journalists in Washington.

Biden and other Western allies have already used unprecedented sanctions as a way of throttling support for Moscow's war in Ukraine, while at the same time supplying Kyiv with both weapons and aid.

But Russia has withstood the initial shock and put its economy on a war footing, ramping up production and recruitment and jailing critics of the invasion.

Meanwhile doubts have been growing over Washington's future commitment to Ukraine. With existing US funding already dried up, former president Donald Trump's allies in the House of Representatives have been stalling $60 billion in new military aid.

Trump, the likely Republican nominee in the November presidential election, opposes helping Kyiv and recently used his sway to kill a US border reform bill that would have also authorized additional aid to Ukraine.

Ukraine's troops are outnumbered and exhausted, while Europe cannot ramp up weapons supplies fast enough without the United States, underscoring the urgency of getting more funding to Kyiv.

Biden slammed Republicans again Monday over the failure to pass the aid package.

"The way they're walking away from the threat of Russia, the way they're walking away from NATO, the way they're walking away from meeting our obligations, it's just shocking," he said.

But he said he would be happy to meet with Mike Johnson, Speaker of the Republican-led House of Representatives, who has told reporters he has no intention of even allowing a vote on the package.

"Sure, I'd be happy to meet with him, if he has anything to say," Biden said.

He added that he hoped that Navalny's death would make a difference when it came to passing the aid, but "I'm not sure."

Analysts have warned Putin may be biding his time, waiting -- and hoping -- for Trump to be reelected, which could reduce support for Kyiv.

Trump had stayed silent for days over the death of Navalny, in the face of growing criticism.

Then on Monday he posted on his Truth Social website that the "sudden death" of the opposition leader had made him "more and more aware of what is happening" -- in the United States.

"It is a slow, steady progression, with crooked, radical left politicians, prosecutors and judges leading us down a path to destruction," he wrote.

The post did not mention the Russian government or Putin.