Russia has said it is not planning an invasion but could take unspecified military action if its security demands are not met

White House National Security Adviser Jake Sullivan warned on Sunday (February 6) that Russian President Vladimir Putin could take military action against Ukraine "any day now".

The border tensions between Russia and Ukraine have heightened in the last couple of weeks with both sides amassing massive troops. However, there are calls to tackle the situation with diplomacy.

The United States and other Western countries have expressed their fears over potential Russian incursion but Kremlin denies it. The escalating tensions have created a war-like situation that could impact Asian countries significantly.

"We are in the window. Any day now, Russia could take military action against Ukraine, or it could be a couple of weeks from now, or Russia could choose to take the diplomatic path instead," Sullivan told the "Fox News Sunday" program.

On Saturday (Feb 5), two US officials said Russia has in place about 70 per cent of the combat power it believes it would need for a full-scale invasion of Ukraine.

Reports have suggested and also satellite images show that Russia has amassed more than 100,000 troops near the border.

Moscow has said it is not planning an invasion but could take unspecified military action if its security demands are not met.

Those include a promise that NATO will never admit Ukraine, a demand the United States and the 30-nation Western security alliance have called unacceptable.

Meanwhile, US President Joe Biden held a telephone call with French President Emmanuel Macron on Sunday, the White House said.

That call came ahead of a visit by Macron to Moscow on Monday, the culmination of days of French contacts with Russia and Ukraine to try to de-escalate tensions.