US President Joe Biden and Russian President Vladimir Putin began their second conversation this month on Thursday afternoon, with rising tensions over Ukraine topping the agenda.
The call, which was requested by Putin, began at 3:35 pm Eastern time (20 35 GMT), according to US officials.
Moscow has alarmed the West by massing tens of thousands of troops near its border with Ukraine in the past two months, following its seizure of Ukraine’s Crimea peninsula in 2014 and its backing of separatists fighting in eastern Ukraine.
Russia denies planning to attack Ukraine and says it has the right to move its troops on its own soil as it likes.
Officials have said the leaders will discuss a range of topics, including upcoming security talks next month, the tense situation in Europe, and ongoing talks with Iran over its nuclear programme.
Both the White House and the Kremlin are expected to provide their summaries of the call after it takes place.
Moscow, worried by what it says is the West’s re-arming of Ukraine, has said it wants legally-binding guarantees NATO will not expand further eastwards, and that certain offensive weapons will not be deployed to Ukraine or other neighboring countries.
The talks between Biden and Putin come ahead of a January 10 US-Russia security meeting, followed by a Russia-NATO session on January 12, and a broader conference including Moscow,Washington and other European countries slated for January 13.
US concerns have not ebbed in recent weeks, according to a senior Biden administration official.
Other US officials said that despite a report over the weekend that Russia would be pulling back about 10 000 troops from its border with Ukraine, they had seen little evidence to support that so far.
“We are at a moment of crisis and have been for some weeks now given the Russian build-up, and it will take a high level of engagement to address this and to find a path of de-escalation,”said one of the US officials, who declined to be named.
US officials are telling Moscow they will take swift economic action against Russia and reinforce NATO in the case of an invasion.
But the US President has been pushing direct diplomacy as an alternative.
Putin has compared the current tensions to the Cold War-era Cuban Missile Crisis in 1962.
Washington regards some of his demands, including restrictions on NATO expansion, as non-starters.
