Diplomats on Monday offered a glimmer of hope that the stand-off in Ukraine could be peacefully resolved as both sides struck a softer tone before more East-West talks.
Russia's Foreign Minister Sergey Lavrov gave negotiators a boost by telling President Vladimir Putin they should have more time to discuss US proposals for the future of European security.
Mr Putin, who is believed by the US and UK to be planning an invasion of Ukraine, was advised that diplomatic options were "far from being exhausted" despite Nato's refusal to consider curbs on its eastward expansion.
Meanwhile, in Kiev, German Chancellor Olaf Scholz played down the prospect of Ukraine joining Nato in the near future — one of Russia's main concerns — by saying this was "not on the order paper".
Asked if this was an olive branch to Russia before he holds talks in Moscow on Tuesday, Mr Scholz did not answer directly, but said he was ready for a "serious dialogue" with Mr Putin.
Ukraine, which has sought to calm fears of an invasion, accused Russia of using the Nord Stream 2 gas pipeline as a "geopolitical weapon" in the high-stakes talks.
Mr Scholz was mounting what was seen as a last-ditch scramble to avoid war after British and US officials briefed that an invasion of Ukraine could come any day.
Russia's build-up of an estimated 130,000 troops near Ukraine, and its military drills on the territory of nearby Belarus, have alarmed western capitals and prompted threats of severe sanctions if Mr Putin orders an attack.
Some airlines are avoiding Ukrainian airspace, while many governments have urged their citizens to leave the territory of the former Soviet republic. All British military training personnel have left Ukraine with only a handful of staff remaining in the embassy, a government spokesman said.
In a call late on Monday, Prime Minister Boris Johnson and US President Joe Biden said there was a "crucial window for diplomacy" in which Russia could step back from military escalation.
Mr Johnson and Mr Biden told Russia that it would face a "protracted crisis" if it invaded Ukraine as well as the package of sanctions being negotiated by western leaders.
They called on European countries to reduce their dependence on Russian gas in a move which "more than any other, would strike at the heart of Russia's strategic interest," a Downing Street representative said.
Meanwhile, Ukraine's ambassador in London, Vadym Prystaiko, walked back a suggestion that Ukraine could shelve its Nato ambitions but told the BBC that Kiev was "ready for many concessions" in talks with Moscow.
In his proposals to Mr Putin, Mr Lavrov said there was potential for dialogue on secondary issues such as arms control and restrictions on military drills, where the US has said it is willing to negotiate.
He said he would advise continuing talks “at this stage” and that there was "always a chance" of an agreement, despite Russia's frustration that Nato will not discuss limits on its eastward expansion.
Mr Scholz said Nato's door should remain open but that it was curious that Russia should put such emphasis on this point when Ukraine's membership of the alliance was not "the task of the hour".
He said Germany expected "clear steps" towards de-escalation from the Kremlin, after saying there was no sensible reason for such a concentration of troops.
"We are seeking a diplomatic solution to this difficult situation," Mr Scholz said. "We are ready for a serious dialogue with Russia about questions of European security."
Mr Scholz spoke alongside Ukrainian President Volodymyr Zelenskiy, who said Ukraine still aspired to join Nato and made no secret of his differences with Germany on the future of the Nord Stream 2 gas pipeline.
Ukraine, the US and Britain all oppose the construction of the pipeline from Russia to Germany, fearing it could be used as a political weapon by the Kremlin.
Mr Scholz again evaded attempts to pin him down on whether the pipeline would be cancelled, as the US insisted it would, as part of what western leaders have repeatedly described as a severe package of sanctions if Russia attacks.
Mr Johnson backed calls to back away from Russian gas on Monday.
“What I think all European countries need to do now is get Nord Stream out of the bloodstream,” he quipped.
“Yank out that hypodermic drip feed of Russian hydrocarbons that is keeping so many European economies going.”
Germany has also caused some consternation by refusing to export weapons to Ukraine, claiming fears of an escalation and the traumatic memory of its invasion of Russia during the Second World War.
Andrij Melnyk, Ukraine’s ambassador in Germany, appealed to Mr Scholz’s government to supply weapons to Kiev in a guest article for Germany's biggest-selling newspaper on Monday.
Mr Scholz said this was not on the table but announced details of further financial support to Ukraine.
Germany's military said the first of 350 extra troops to bolster Nato forces in Lithuania were sent on Monday.
France's Foreign Minister Jean-Yves Le Drian warned on Monday that "all the elements" were in place for Russia to wage a "major offensive" against Ukraine.
"Are there all the elements for a major offensive by Russian forces in Ukraine? Yes there are, it's possible, it's possible quickly," Mr Le Drian told France 5 television.
But there was nothing to suggest Moscow had yet made a decision, he said.
"There is still a diplomatic solution, yes that's for sure," Mr Le Drian said. "There is an untenable military situation with a growing escalation. There is an urgent need for de-escalation.
"Putin wants to prevent Ukraine from having its sovereignty. If the sovereignty or the integrity of Ukraine were challenged by a significant intervention on the part of Russia, then there would be massive consequences, massive sanctions."
