Happening now breaking news. The Pentagon says Russia could invade Ukraine with

little to no warning after another buildup of its troops at the border. The

U.S. is closing, its embassy and key amid growing

concerns and attack might happen this week. Also breaking. We have new reporting on what Rudy Giuliani may be willing to reveal under oath to the January 6th Select Committee and the line the former Trump lawyer does not intend to cross.

Also tonight, Dr Anthony Fauchy, standing by

to join us live to answer questions

about the new delay in authorizing COVID vaccines

for younger children.

Many parents are increasingly frustrated as their kids remain

unprotected. We want to welcome our viewers here in the United States and around the world.

I'm Wolf Blitzer, you're in the situation room.

This is CNN breaking news.

Tonight the United States is closing its embassy in the Ukrainian capital

as the Biden administration acknowledges this could be the week.

This could be the week that Russia launches an invasion.

We have a team of correspondence on the ground in Ukraine, in Russia, here in the United States,

as we cover this breaking story first. Let's go to our chief White House correspondent,

Caitlin Collins.

Caitlin, as this crisis clearly escalates,

what is happening behind closed doors

where you are at the White House.

There's a real level of concern here, Wolf,

...