The Kremlin has revealed that Russian President Vladimir Putin told his US counterpart Joe Biden that the imposition of new "unprecedented" sanctions could result in a complete breakdown of relations between the two countries.

The presidents spoke via conference call on Thursday, amid ongoing tensions between Moscow and the West over Ukraine. The US and its allies have repeatedly warned of the possibility of a Russian invasion of its neighbor, citing an alleged buildup of troops within the country's borders. The Kremlin has dismissed the speculation as unfounded, insisting that it has no intention of attacking its fellow former Soviet republic.

Biden apparently doubled down on the allegation, however, threatening to impose wide-ranging sanctions aimed at crippling Russia's economy, its financial sector, and its military industry were there to be any "further escalation of the situation along the Ukrainian border," Kremlin aide Yury Ushakov outlined.

If Washington followed through with this threat, it should be prepared for a total collapse of its already strained relationship with Moscow, he noted.

"If the West, under any pretext, decides to impose these unprecedented sanctions, it could lead to a complete breakdown of relations between our countries, and would deal a very serious blow to Russia-West relations as a whole," Ushakov added.

He went on to assert that a new round of US sanctions would be a "colossal mistake" that should be avoided at all costs, including for the sake of future generations.

It also emerged that the American leader had apparently made a pledge not to supply assault weaponry to Ukraine.

"Biden made it clear that the US does not intend to deploy offensive strike weapons in Ukraine," Ushakov outlined.

He explained that this had been one of the goals Moscow had hoped to achieve via the proposals for security guarantees it made to the US and NATO, earlier this month. 

During the 50-minute call, Putin once again outlined the main principles of Russia's security requirements, which envisage a halt to NATO's eastward expansion. The Russian leader reportedly stressed that any potential deal with the West should include legally binding guarantees as to Russia's security, with Ushakov noting that Biden appeared to have taken that demand "quite seriously."

The Biden administration nonetheless refused to confirm that the US leader had made any commitments during his conversation with Putin. "We are not going to draw conclusions, and there were certainly no declarations as to intentions from this conversation. But, regardless, our focus is really on actions and on indicators – not on words, at this point," a White House official said shortly after the conversation concluded. 

The Kremlin revealed that security talks would be held in three formats: Between Moscow and Washington in Geneva, at the Russia-NATO level in Brussels, and at the Organization for Security and Co-operation in Europe in Vienna. The bilateral meetings will begin on January 9.