Russian officials have denied reports Moscow sent Washington a written response to a US proposal aimed at de-escalating the Ukraine crisis.

It comes a day after the two countries exchanged sharp accusations at the United Nations (UN) Security Council and as a series of high-level meetings in Moscow and Kyiv were underway.

The Kremlin is seeking legally binding guarantees from the US and Nato that Ukraine will never join the bloc, deployment of Nato weapons near Russian borders will be halted and the alliance’s forces will be rolled back from Eastern Europe.

The demands, rejected by Nato and the US as non-starters, come amid fears that Russia might invade Ukraine, stoked by the build-up of an estimated 100,000 Russian troops near the border.

Ukraine RussiaAn Ukrainian serviceman observes pro Russian separatists’ positions through a periscope from a trench at a frontline position in the Donetsk region on Monday January 31 2022 (AP Photo/Vadim Ghirda/PA)

Talks between Russia and the West have so far failed to yield any progress.

Washington has provided Moscow with a written response to the demands, and on Monday three Biden administration officials said the Russian government sent a written response to the US proposals.

A State Department official declined to offer details about the document, saying it “would be unproductive to negotiate in public” and they would leave it up to Russia to discuss the counterproposal.

But deputy foreign minister Alexander Grushko on Tuesday told Russia’s state RIA Novosti news agency this was “not true”.

The agency also cited an unnamed senior diplomat in the Russian Foreign Ministry as saying that foreign minister Sergey Lavrov sent a message to his Western colleagues, including US secretary of state Antony Blinken about “the principle of indivisibility of security”, but it was not a response to Washington’s proposals.

On Tuesday, Kremlin spokesman Dmitry Peskov told reporters there had been “confusion” and said Russia’s response to the US proposals was still in the works.

What was passed on to Western officials “were other considerations on a somewhat different issue,” Mr Peskov said.

On Monday, Russia accused the West of “whipping up tensions” over Ukraine and said the US had brought “pure Nazis” to power in Kyiv as the UN Security Council held a stormy debate on Moscow’s troop build-up near its southern neighbour.

US ambassador Linda Thomas-Greenfield responded by saying Russia’s growing military force along Ukraine’s borders was “the largest mobilisation” in Europe in decades, adding that there has been a spike in cyber attacks and Russian disinformation.

The harsh exchanges came after Moscow lost an attempt to block the meeting and reflected the gulf between the two nuclear powers.

It was the first open session where all protagonists in the Ukraine crisis spoke publicly, even though the UN’s most powerful body took no action.

More high-level diplomacy is expected this week.

Russian President Vladimir Putin met with Hungarian Prime Minister Victor Orban in Moscow on Tuesday and said in his opening remarks that the Kremlin’s security demands would be discussed. Mr Orban, in turn, stressed that no European leader wants a war in the region.

Later in the day, Mr Lavrov and Mr Blinken were expected to have a phone call, while British Prime Minister Boris Johnson was scheduled to meet with Ukrainian President Volodymyr Zelenskyy in Kyiv.

Meanwhile, Mr Zelenskyy signed a decree on Tuesday expanding the country’s army by 100,000 troops, bringing the total number to 350,000 in the next three years, and raising army wages.

Mr Zelenskyy, who in recent days has sought to calm the nation, said he signed “this decree not because of a war.”

He added: “This decree is so that there is peace soon and further down the line.”

The decree ends conscription starting from January 1 2024 and outlines plans to hire 100,000 troops over the next three years.