Joe Biden
Joe BidenREUTERS/Kevin Lamarque

The White House said on Thursday that President Joe Biden warned Ukraine's President that there is a "distinct possibility" Russia could take military action against Ukraine in February, The Associated Press reports.

Ukrainian President Volodymyr Zelensky said that he had held a lengthy conversation with Biden about the tensions between Ukraine and Russia.

“Discussed recent diplomatic efforts on de-escalation and agreed on joint actions for the future. Thanked President Biden for the ongoing military assistance. Possibilities for financial support to Ukraine were also discussed,” he tweeted.

Later, a senior Ukrainian official told CNN that Biden had told Zelensky that a Russian invasion of Ukraine is now virtually certain and that his country needs to "prepare for impact”.

However, National Security Council spokesperson Emily Horne denied that Biden had made such comments, explaining that the US President had merely amplified concerns that administration officials have been making for some time.

"President Biden said that there is a distinct possibility that the Russians could invade Ukraine in February," she said. "He has said this publicly and we have been warning about this for months. "

The White House said Biden told Zelensky he was "exploring additional macroeconomic support to help Ukraine´s economy" as it comes under pressure as a result of Russia's military buildup.

Biden said earlier this week that he would consider personally sanctioning Russian President Vladimir Putin if Russia invades Ukraine.

"If he were to move in with all those forces, it would be the largest invasion since World War II. It would change the world," Biden told reporters at an unannounced stop at a local business in Washington, according to ABC News.

Asked about what would lead him to deploy troops staging nearby, Biden said that depends on "what Putin does or doesn't do" but he repeated that American forces would not move into Ukraine.

On Monday, the Pentagon announced that Defense Secretary Lloyd Austin had placed around 8,500 US-based troops on "heightened alert" for rapid deployment to assist NATO if needed.

No decision to deploy them had been made, though, according to Pentagon spokesman John Kirby, who noted that the US could also offer troops already stationed in Europe.

Later in the day, Biden held a video call with the leaders of the European Commission, European Council, NATO, France, Germany, Italy, Poland and the United Kingdom.

The White House said the call lasted 1 hour and 20 minutes.

The conversation came a day after the State Department ordered the families of all American personnel at the US Embassy in Ukraine to leave the country amid heightened fears of a Russian invasion.

The department told the dependents of staffers at the US Embassy in Kiev that they must leave the country. It also said that non-essential embassy staff could leave Ukraine at government expense.

Hours later, the State Department warned American citizens not to travel to Russia amid tensions with Ukraine.