US President Joe Biden on Monday warned Moscow that the death of jailed opposition leader Alexei Navalny would damage Russia's relations with the US and other nations as he sought to signal a tough tone before this week's summit with President Vladimir Putin.
Mr Biden said Navalny’s death would be another indication that Russia has "little or no intention of abiding by basic, fundamental human rights".
“It would be a tragedy. It would do nothing but hurt his relationships with the rest of the world, in my view, and with me," the US president said at a press conference at Nato headquarters in Brussels.
Authorities jailed Mr Navalny in January after he returned to Russia from Germany, where he had received treatment after being poisoned.
Questions have swirled around Mr Navalny's health since his incarceration. In April, he ended a 24-day hunger strike after he received treatment for back pain and numbness in his legs and hands.
But in an interview that aired on Monday, Mr Putin told NBC News he could not guarantee Mr Navalny would leave prison alive.
Mr Putin also denied initiating the attempt to kill Mr Navalny by poisoning him with a nerve agent, though the US intelligence community assesses with “high confidence” that the Russian Federal Security Service was behind the assassination attempt.
Before Wednesday's summit in Geneva, the White House has sought to play down the prospect of any major breakthroughs in the acrimonious relationship between Washington and Moscow.
Mr Biden vowed the US would “respond in kind” to any Russian cyber attacks or other malicious activities while clarifying “where the red lines are".
“We’re going to make clear to President Putin that there are areas where he can co-operate if the chooses," Mr Biden said.
“If he chooses not to co-operate and acts in a way that he has in the past relative to cyber security and some other activities, then we will respond.”
The Biden administration has slapped sanctions on 32 Russian citizens and entities over the jailing of Mr Navalny as well as their alleged role in cyber attacks and interference in US elections.
On the question of Ukraine and its conflict with Moscow, the US president did not shut the door to Kiev's potential entry into Nato.
Such a move would allow Ukraine to invoke the alliance’s Article 5 collective defence clause against Russia for its ongoing occupation of Ukrainian territory.
“It depends on whether they meet the criteria,” Mr Biden said.
“The fact is they still have to clean up corruption. The fact is they have to meet the criteria to get into the action plan, so school’s out on that question.”
“In the meantime, we will do all that we can to put Ukraine in the position to be able to resist Russian physical aggression.”
The Biden administration announced an additional $150 million in security aid for Ukraine last week.
During his speech, the US president also waded into domestic politics after he was asked about Nato members’ ability to maintain faith in American leadership following the failed January 6 insurrection on the Capitol.
“It is a shock and surprise that what’s happened in terms of the consequence of [former president Donald] Trump’s phoney populism has happened,” Mr Biden said.
"It is disappointing that so many of my Republican colleagues in the Senate – that I know know better – have been reluctant to take on, for example, any meaningful investigation."
Prior to the Trump administration, US presidents had typically refrained from wading into partisan domestic politics while travelling overseas.
“It’s appropriate to say that the Republican Party is vastly diminished in numbers,” said Mr Biden.
“The leadership of the Republican Party is fractured. And the Trump wing of the party is the bulk of the party, but it makes up a significant minority of the American people.”