With diplomats publicly pessimistic, the US and Russia have begun difficult talks in Geneva that Washington hopes can avert the danger of a new Russian invasion of Ukraine without conceding to the Kremlin's security demands.
Russian Deputy Foreign Minister Sergei Ryabkov said over the weekend it was entirely possible that the diplomacy could end after a single meeting, and US Secretary of State Antony Blinken played down expectations for the high-stakes talks.
"I don't think we're going to see any breakthroughs in the coming week," Blinken said in a CNN interview on Sunday.
The talks began on Monday at the US diplomatic mission in Geneva with US-Russia relations at their most tense since the Cold War ended three decades ago. Discussions will then move on to meetings in Brussels and Vienna.
Deputy Secretary of State Wendy Sherman, the No.2 official in the US State Department, said in a Tweet from Geneva that "the US will listen to Russia's concerns and share our own".
No discussions on European security would be held without the presence of other allies, she said.
Nearly 100,000 Russian troops are gathered within reach of the border with Ukraine in preparation for what Washington and Kiev say could be an invasion, eight years after Russia seized the Crimea peninsula from Ukraine.
Russia denies invasion plans and said it is responding to what it calls aggressive and provocative behaviour from the NATO military alliance and Ukraine, which has tilted toward the West and aspires to join NATO.
Last month, Russia presented a sweeping set of demands that include a ban on further NATO expansion and an end to the alliance's activity in central and eastern European countries that joined it after 1997.
The United States and NATO have dismissed large parts of the Russian proposals as non-starters, raising questions about whether there is any middle ground.
"Naturally, we will not make any concessions under pressure," said Ryabkov, who will lead the Russian delegation in Geneva.
US President Joe Biden has repeatedly warned Russian President Vladimir Putin that the US and European allies would impose unprecedented sanctions if Russia chose to invade Ukraine. Putin responded that sanctions could lead to a "complete breakdown in ties."
In a preliminary meeting with Ryabkov on Sunday evening, Sherman emphasised Washington's commitments to sovereignty, territorial integrity "and the freedom of sovereign nations to choose their own alliances," the State Department said.
Ryabkov told reporters his meeting with Sherman had been "complex but businesslike," Russian news agency Interfax said.
Ryabkov has compared the situation to the 1962 Cuban missile crisis when the world stood on the brink of nuclear war.
The United States and allies have said they are prepared to discuss the possibility of each side restricting military exercises and missile deployments in the region.