US Secretary of State Antony Blinken and Russian Foreign Minister Sergei Lavrov met for talks in Geneva on Friday amid mounting fears that Russia could be about to invade Ukraine.
“This is a critical moment,” Mr Blinken said in his opening remarks.
The US and Russia “don’t expect to resolve our differences here today”, he added, but hoped to test whether diplomacy was still a viable option.
Speaking afterwards, Mr Lavrov described the talks as open and useful.
Moscow has 100,000 troops near its borders with Ukraine, but denies planning to invade.
Across the table in a luxury Swiss hotel, Mr Blinken warned his Russian counterpart of a “united, swift and severe” response if Russia did take that step.
President Vladimir Putin has issued demands to the West which he says concern Russia’s security, including that Ukraine be stopped from joining Nato.
He wants the Western defensive alliance to abandon military exercises and stop sending weapons to eastern Europe, which Moscow sees as its backyard.
At a press conference after the meeting, Mr Lavrov accused Nato of working against Russia. He reiterated Moscow’s position that it has “never threatened the Ukrainian people” and has no plans to attack Ukraine.
The US will present Russia with a written response to its security red lines “next week”, he added. Another meeting is expected to follow when Russia has examined it.
Mr Blinken told reporters the US is prepared to pursue possible means of addressing Russian concerns in the spirit of reciprocity.
Beforehand, analysts mooted this might include more transparency on military exercises in the region, or reviving restrictions on missiles in Europe. These rules were previously set out in the Intermediate-Range Nuclear Forces Treaty, a Cold War-era pact that the US scrapped in 2019, after accusing Russia of violating the deal.
Mr Blinken also urged Russia to stop its aggression towards Ukraine, saying the troop build-up gives it the ability to attack Ukraine from the south, east and north.
He said the US knows from experience that Moscow also has an “extensive playbook” of non-military ways of furthering its interests, including cyber attacks.
Mr Blinken said the talks also touched on Iran and negotiations over its nuclear capabilities, which he called an example of how the US and Russia can work together on security issues.
Tensions over Ukraine
The talks between the two diplomats came just a day after Russia unveiled plans for naval drills involving more than 140 warships and more than 60 aircraft, seen as a show of strength.
Also on Thursday, the US warned that Russian intelligence officers had been recruiting current and former Ukrainian government officials to step in as a provisional government and cooperate with an occupying Russian force in the event of an invasion.
The US Treasury Department imposed sanctions on two current Ukrainian members of parliament and two former government officials accused of being part of the plot.
Mr Blinken arrived in Geneva after a trip to Kyiv to show support for Ukraine, and talks with Britain, France and Germany in Berlin.
Several European nations have now moved to bolster Nato’s military deployment in eastern Europe. Spain is sending warships to join Nato naval forces in the Mediterranean and the Black Sea, and Denmark also said it would send a frigate to the Baltic Sea.
French President Emmanuel Macron has offered to send troops to Romania.
Earlier this week, Britain announced it was supplying Ukraine with extra troops for training and defensive weapons.
In a speech on Friday, UK Foreign Secretary Liz Truss called on Mr Putin to “desist and step back from Ukraine before he makes a massive strategic mistake” that would lead to terrible loss of life.
President Biden had triggered questions about the consistency of the US line on Ukraine on Wednesday, when he bleakly predicted that Russia “will move in” on Ukraine, but appeared to suggest a “minor incursion” could attract a weaker response from the US and its allies.
The message drew a rebuke from Ukrainian President Volodymyr Zelensky, who tweeted: “There are no minor incursions. Just as there are no minor casualties and little grief from the loss of loved ones.”
Mr Biden then sought to clarify by saying any Russian troop movement across Ukraine’s border would qualify as an invasion and that Moscow would “pay a heavy price”.
