US Secretary of State Antony Blinken and Russian Foreign Minister Sergey Lavrov talked briefly on Thursday at a meeting of top diplomats from the Group of 20 nations in the first high-level meeting in months between the two countries.

US officials said Blinken and Lavrov chatted for roughly 10 minutes on the sidelines of the G20 conference in New Delhi. The short encounter came as relations between Washington and Moscow have plummeted while tensions over Russia’s war with Ukraine have soared.

A senior US official said Blinken used the discussion to make three points to Lavrov: that the US would support Ukraine in the conflict for as long as it takes to bring the war to an end, that Russia should reverse its decision to suspend participation in the New Start nuclear treaty and that Moscow should release detained American Paul Whelan.

The official, who spoke to reporters on the condition of anonymity to discuss the private conversation, said Blinken had “disabused” Lavrov of any idea they might have that US support for Ukraine is wavering.

The official declined to characterise Lavrov's response but said Blinken did not get the impression that there would be any change in Russia's behaviour in the near term.

Lavrov, who did not mention the meeting with Blinken, told reporters that Moscow will continue to press its action in Ukraine. He shrugged off Western claims of Russia’s isolation, saying “we aren’t feeling isolated. It’s the West that has isolated itself, and it will eventually come to realise it.”

He said Russia remains open to talks on ending the conflict in Ukraine, but he accused the West of effectively blocking such talks.

“They are calling on us to have talks, but I don’t remember any Western colleagues calling on Ukraine to have talks,” he said. “They are encouraging Ukraine to continue the war.”

Russia had no immediate comment on the substance of the conversation, but Russian Foreign Ministry spokesperson Maria Zakharova said Blinken had asked to speak to Lavrov.

It was their first contact since last summer, when Blinken called Lavrov by phone about a US proposal for Russia to release Whelan and formerly detained WNBA star Brittney Griner.

Griner was later released in a swap for imprisoned Russian arms dealer Viktor Bout (AP)