"American citizens should leave now," Biden said in an interview with NBC News anchor Lester Holt.
“It’s not like we’re dealing with a terrorist organization. We’re dealing with one of the largest armies in the world. It’s a very different situation, and things could go crazy quickly,” he said.
Holt asked Biden what scenario could prompt him to send troops to rescue Americans fleeing the country. Biden replied: “There’s not. That's a world war when Americans and Russia start shooting at one another.”
"We’re in a very different world than we’ve ever been," he added.
Tune in for more Friday at 7 a.m. ET on "TODAY" and Sunday during NBC’s Super Bowl pregame show.
Separately on Thursday, the State Department issued an advisory warning that the U.S. “will not be able to evacuate U.S. citizens in the event of Russian military action anywhere in Ukraine.” It warned that regular consulate service — including aiding citizens trying to leave the country — would be “severely impacted.”
According to a U.S. military and intelligence assessment, the Russian military could launch a full-scale invasion, with tanks that potentially could reach Kyiv, the capital, within 48 hours.
Biden argued that if Russian President Vladimir Putin is "foolish enough to go in, he’s smart enough not to, in fact, do anything that would negatively impact on American citizens."
"Have you ever told him that?" Holt asked.
"Yes," Biden responded.
"You’ve told him that, that Americans will be a line that they can’t cross?" Holt asked.
"I didn’t have to tell him that. I’ve spoken about that. He knows that," Biden said.
A senior administration official said Friday that Biden would host a virtual meeting on Ukraine with the leaders of the United Kingdom, France, Germany, Canada, the European Union, NATO, Italy, Romania and Poland in the morning. The White House said the leaders would "discuss our shared concerns about Russia’s continued buildup of military forces around Ukraine and continued coordination on both diplomacy and deterrence."
Indoor mask mandates
On the issue of lifting indoor mask mandates, Biden signaled that it may be too soon to end the requirements that apply to federal government offices and public buildings.
California, Connecticut, Delaware, New Jersey, New York and Oregon — all states led by Democratic governors — announced this week that they were easing or ending mask mandates.
"I've committed that I would follow the science as put forward by the CDC and federal people, and I think it’s probably premature, but it’s, you know, it’s a tough call," Biden said, referring to the Centers for Disease Control and Prevention.
Asked whether children should have to wear masks in schools, another debate raging at the state level, Biden pointed to schools that are being reopened. The CDC suggests wearing masks in places where the new case rate is higher than 50 cases per 100,000 people or the testing positivity rate exceeds 8 percent, a recommendation that still covers most of the country.
"When I got in office, only 46 percent of schools were opened. Now 98 percent of them are open, and they're wearing masks," Biden said. "What’s happening is every day that goes by, children are more protected. We’re now on the verge of being able to have shots for children under the age of 7 and young children, and so the more protection they have, probably you’re going to see less and less requirement to have the mask."
Biden said there has been a "deep dive" on four candidates for his pending nomination to replace Justice Stephen Breyer, who announced last month that he will step down from the Supreme Court at the end of the current term.
"The shortlist are nominees who are incredibly well-qualified and documented," he said. "They were the honor students. They have come from the best universities. They have experience, some on the bench, some on the practice of law."
Breyer is one of three liberal justices on the court serving alongside six conservatives, and his decision to retire after more than 27 years will not change the political leanings of the court.
Biden has said he will fulfill his campaign promise to select a Black woman, which some Republicans have criticized.
Biden predicted that whoever he picks will find some support among Republicans.
"I'm not looking to make an ideological choice," he said. "I'm looking for someone that replaces Judge Breyer with the same kind of capacity Judge Breyer has, with an open mind, who understands the Constitution, interprets it in a way that is consistent with the mainstream interpretation of the Constitution."
Build Back Better
Biden also addressed the failure of Democrats to advance his social safety net bill and attributed that partly to a messaging problem.
"I think I haven't sold it well," Biden said, adding that he thinks people are now realizing what the proposal would provide.
Negotiations on the legislation collapsed at the end of last year after centrist Sen. Joe Manchin, D-W.Va., said he would not support the bill. Manchin has since said he's open to restarting talks, but that negotiators would be "starting from scratch."
Democrats are discussing sweetening the deal for Manchin by adding deficit-reduction provisions, a source familiar with the talks said.