US places up to 8,500 troops on alert for possible deployment to Eastern Europe amid Russia tensions - CNN

US Secretary of Defense Lloyd Austin issued the prepare to deploy orders at the direction of President Joe Biden, the latest step the US has taken to prepare for a potential Russian invasion of Ukraine that officials have warned could be imminent.

He noted the NATO Response Force "comprises around 40,000 multinational troops."

Earlier on Monday CNN reported the Biden administration was in in the final stages of identifying specific military units it wants to send to Eastern Europe, according to multiple US and defense officials.

Biden discussed options for bolstering US troop levels in the Baltics and Eastern Europe with his top military officials during a briefing at Camp David on Saturday, according to a senior official.

The goal of sending military reinforcements to Eastern Europe would be to provide deterrence and to reassure allies, and there's been no suggestion US combat troops would deploy to Ukraine or take part in any combat roles.

Kirby noted the US does have military advisers in Ukraine.

Kirby would not say where the US troops might deploy, but said the US has "made it clear to the Eastern flank allies that we're prepared to bolster their capabilities if they need it."

"In the event of NATO's activation of the NRF or a deteriorating security environment, the United States would be in a position to rapidly deploy additional brigade combat teams, logistics, medical, aviation, intelligence, surveillance and reconnaissance, transportation and additional capabilities into Europe," Kirby said.

"I had a very, very, very good meeting," Biden said.

A White House readout of the call said the leaders discussed "preparations to impose massive consequences and severe economic costs on Russia for such actions as well as to reinforce security on NATO's eastern flank."

Following the virtual meeting with the leaders of the US, France, Germany, Italy, Poland, the United Kingdom and the European Union, NATO Secretary General Jens Stoltenberg said, "We agree that any further aggression by Russia against Ukraine will have severe costs."

Biden and his national security team have been refining military plans "for all scenarios," including the option of sending troops to Eastern Europe ahead of a potential Russian invasion of Ukraine, the White House said Monday.

White House press secretary Jen Psaki said a decision to increase US troops could come ahead of Russian forces moving across the Ukrainian border, but said such a move did not amount to a shift in Biden's thinking.

"We have never ruled out the option of providing additional assistance in advance of an invasion.

NATO countries are also sending additional ships and fighter jets to Eastern Europe and putting forces on standby, Stoltenberg said in a statement Monday.

"NATO will continue to take all necessary measures to protect and defend all Allies, including by reinforcing the eastern part of the Alliance," he said.

US and UK reduce embassy staffing in Kyiv

The Ukrainian Defense Ministry's latest intelligence assessment found that Russia has now deployed more than 127,000 troops in the region, while US officials have said Russia is in a position to launch an invasion at any time.