Russian President Vladimir Putin has warned President Joe Biden that imposing new sanctions over Ukraine could lead to a complete breakdown in relations.
In a phone call late on December 30, Vladimir Putin said such sanctions would be a “colossal mistake”.
President Biden, meanwhile, told Vladimir Putin that the US and its allies would respond decisively to any invasion of Ukraine.
The call, requested by Russia, was the pair’s second such conversation this month and lasted for almost an hour.
It marked the latest effort to defuse tensions over Ukraine’s eastern border with Russia, where Ukrainian officials say more than 100,000 Russian troops have been sent.
The build-up has prompted concern in the West, with the US threatening Vladimir Putin with sanctions “like none he’s ever seen” if Ukraine comes under attack.
Russia, however, denies it is planning to invade Ukraine and says the troops are there for exercises. It says it is entitled to move its troops freely on its own soil.
Although the two sides exchanged warnings during the call, Russian foreign policy adviser Yuri Ushakov told reporters shortly after that Vladimir Putin was “pleased” with the conversation. He added that it had created a “good backdrop” for future talks.
US and Russian officials are set to meet for in-person talks in Geneva next month, and the White House said President Biden urged his Russian counterpart to pursue a diplomatic solution.
In a holiday message before December 30 call, Vladimir Putin told Joe Biden he was “convinced” the pair could work together based on “mutual respect and consideration of each other’s national interests”.
His spokesman, Dmitry Peskov, said Moscow was “in the mood for a conversation”.
Ukraine’s defense minister told parliament at the start of December that Russia had massed tens of thousands of troops near the border, and could be gearing up for a large-scale military offensive at the end of January.
Russia has argued the military build-up at the border is a protective measure against NATO, the Western military alliance. It wants legally binding guarantees that NATO will not expand further east, and that certain weapons will not be sent to Ukraine or any neighboring countries.
The US has rejected what it styles as a Kremlin bid to control the future of independent countries.
Ukraine has not been offered NATO membership, but has close ties with the bloc.
Tensions between Russia and Ukraine are nothing new. In 2014, Russia annexed Ukraine’s Crimean Peninsula and soon after started to back a separatist insurgency in Ukraine’s east that has seen some 14,000 people killed in periodic fighting.
Washington and its European allies have warned Russia to expect severe economic sanctions if troops do cross into Ukraine again.