Senior US officials stated on Sunday that they could not confirm claims that Russia is planning an invasion of Ukraine on Wednesday, but that they would try to avert a "surprise strike" by disclosing what they know about Russia's plans.

White House National Security Adviser Jake Sullivan reiterated that a Russian invasion may begin at any time, and President Joe Biden has stated that if an invasion occurs, he will help Ukraine and defend NATO territory.

"We can't forecast the exact day, but we've been saying for a while that we're in the window, and an invasion — a big military action — by Russia in Ukraine could start any day now. "That includes the week before the end of the Olympics," Sullivan said on CNN's 'State of The Union,' when questioned about the possibility of a Wednesday date.

"We will defend every inch of NATO territory, every inch of Article Five area, and we believe Russia fully gets that message," Sullivan said in a separate appearance with CBS' 'Face the Nation.'

On Sunday, Pentagon spokesman John Kirby also declined to confirm reports about the Wednesday date. "I'm not in a position to validate those stories," Kirby said on 'Fox News Sunday'.

"and, once again, these assessments are based on a range of sources. and not only inside intelligence but also what we're witnessing in plain sight, "Kirby stated. "More than 100,000 troops are currently stationed around Ukraine's border."