President Joe Biden meets with Russian President Vladimir Putin, June 16, 2021, in Geneva, Switzerland. Biden and Putin are scheduled to speak Thursday, Dec. 30, as the Russian leader has stepped up his demands for security guarantees in Eastern Europe. AP
Shortly after taking office earlier this year, Biden gives a tough speech ditching his predecessor Donald Trump's muted approach to Moscow and Putin, for whom Trump had voiced admiration.
"I made it clear to President Putin that the days of the United States rolling over in the face of Russia's aggressive actions, interfering with our elections, cyber attacks and poisoning its citizens are over," Biden said in February.
The Kremlin slams what it calls Biden's "very aggressive and unconstructive rhetoric".
In an interview in March, Biden says Putin will "pay a price" for allegedly trying to undermine his candidacy in the US 2020 election.
Asked if he thought Putin was "a killer", Biden replies, "I do."
The comments spark the biggest crisis between Russia and the US in years, with Moscow recalling its ambassador and warning that ties were on the brink of outright "collapse".
Putin also mocks Biden, saying, "It takes one to know one."
'Time to de-escalate'
A bid to cool tensions comes in April when Biden, after announcing sanctions against Russia, says "now is the time to de-escalate".
During a phone call, Biden says he was "clear with President Putin that we could have gone further" but adds that Washington is "not looking to kick off a cycle of escalation and conflict with Russia".
He proposes a summit to discuss Russian sabre-rattling on Ukraine, the treatment of jailed Putin opponent Alexei Navalny, and other flashpoints.
Before their summit in Geneva on June 16, Biden does not let up, saying the US will push the Kremlin on its human rights record.
On the eve of the summit, Biden calls Putin "tough" and "a worthy adversary".
Tellingly, the two men do not hold a joint press conference after three and a half hours of talks.
However, they agree to return ambassadors to each other's capitals.
Putin said he sensed "no animosity" while Biden agreed the talks had been "constructive".
A Russia-based hacker group is blamed for a massive ransomware attack in late June that hits about 1,500 businesses.
It is taken offline days after Biden calls on Putin to act.
Russia is pointedly not invited to a 30-nation anti-cyber crime summit in Washington in October.
'His tundra is burning'
Biden lays into Putin for not attending the COP26 climate conference in Glasgow in October.
"His tundra is burning -- literally... He has serious, serious climate problems, and he is mum on willingness to do anything," Biden said.
Tensions escalate further in late November as Ukraine claims Russia is massing 100,000 troops on its border.
Putin denies Russia plans to invade Ukraine, but says he wants the US to promise that Ukraine will never join NATO.
In a two-hour virtual summit on December 7, Biden warns Putin of "strong economic and other measures in the event of military escalation" in Ukraine. Putin calls for guarantees of a freeze on NATO's expansion.
On December 17, Russia unveils proposals to contain the US and NATO in the former Soviet Union and Eastern Europe, calling for urgent negotiations with Washington. The US says it is ready to talk in consultation with the EU.
On December 21, Putin warns that Russia is prepared to take "military-technical measures" in response to "unfriendly" Western actions over the Ukraine conflict.
On the 28th, the US condemns the closure of the prominent rights group Memorial International by Russia's Supreme Court.
On Thursday Biden and Putin will speak by telephone, setting the tone for US-Russia security talks on January 10, 2022.
Biden will offer his Russian counterpart a diplomatic path forward on the Ukraine crisis, a US official says, while Putin says he is "convinced" that "effective dialogue" between Moscow and Washington is possible.