Happening now breaking news the White House issues its most dire warning yet about

the threat of a Russian attack on Ukraine saying an invasion could happen at any time

including during the Olympics.

Tonight, chilling new information about how Vladimir Putin may launch a deadly war.

Also breaking, the FDA just postponed a critical meeting on the Pfizer vaccine for children under age five

will tell you what's behind the delay and what it could mean for the bigger push to

move beyond the pandemic. And a new state of emergency is in effect in Canada as protests by truckers cut off major routes into the U.S.

Officials now threatening to use force as the blockade's crippled trade and cause economic pain on both sides of the border.

Welcome to our viewers in the United States and around the world.

Wolflitzer is off today.

I'm Jim Acosta and you're in the situation room. This is CNN breaking news.

We begin with the strongest signals yet from the Biden administration that the Russia-Ukraine crisis

could explode at any moment.

Our correspondence and analysts are standing by in Ukraine in Russia and here in the United States

as we cover this breaking story as only CNN can.

First let's go to our White House correspondent,

M.J. Lee, after weeks of US efforts to prevent an invasion,

time appears to be running out.

That's right, the clock still is ticking and while in the last 24 hours we have seen a notable

shift in tone while U.S. administration officials are saying they still have not

determined whether Russia will in fact invade Ukraine they say a potential

invasion could come sooner than previously expected and they are issuing a stern warning to American

...