US Secretary of Defense Lloyd Austin has issued deployment orders under President Joe Biden, the latest US move to prepare for a possible Russian invasion of Ukraine officials have warned that it could be imminent.

Kirby said “the bulk” of the US troops placed on heightened alert were intended to reinforce NATO’s rapid reaction force, but added that they would be “postulated to be ready for any other eventuality as well.”

As of Monday afternoon, no final troop deployment decisions had been made, Kirby said.

“The United States has taken steps to strengthen the readiness of its forces at home and abroad, so it is ready to respond to a range of contingencies, including response force support of NATO if activated,” Kirby said. He noted that the NATO Response Force “includes approximately 40,000 multinational troops.”

Earlier Monday, CNN reported that the Biden administration is in the final stages of identifying specific military units it wants to send to Eastern Europe, according to several U.S. and defense officials.

Biden discussed options for boosting 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.

Sending military reinforcements to Eastern Europe would be aimed at deterring and reassuring allies, and there has been no suggestion that US combat troops will deploy to Ukraine or participate in combat roles. Kirby noted that the United States had military advisers in Ukraine.

Kirby did not say where American troops could deploy, but said the United States had “made it clear to allies on the eastern flank that we were ready to reinforce their capabilities if needed.”

“In the event of NATO activation of the NRF or a deterioration in the security environment, the United States would be able to rapidly deploy additional brigade combat teams, logistics, medical , aviation, intelligence, surveillance and reconnaissance, transportation and additional capabilities in Europe,” Kirby said.

The news comes amid US warnings that a possible Russian invasion of Ukraine could be imminent. On Sunday, the State Department reduced the staff of the United States Embassy in Kyiv, Ukraine, with the departure of non-essential staff and family members in “an excess of caution”.

Biden holds calls with European leaders

Biden lasted 80 minutes video call with European leaders on Monday afternoon, which the White House said was part of the administration’s consultation and coordination with European allies in response to Russia’s military buildup.

Biden told reporters at the White House there was “complete unanimity” with European leaders on the call. “I had a very, very, very good meeting,” Biden said.

A White House reading of the appeal said the leaders had discussed “preparations to impose massive consequences and severe economic costs on Russia for such actions as well as to strengthen security on the eastern flank of the NATO”.

Following the virtual meeting with the leaders of the United States, France, Germany, Italy, Poland, United Kingdom and the European Union, the Secretary General of the NATO, Jens Stoltenberg, said: “We agree that any further Russian aggression against Ukraine will have significant costs. “

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

White House press secretary Jen Psaki said a decision to increase US troops could precede Russian forces crossing the Ukrainian border, but said such a move did not constitute a change in the Biden thought.

“We have never ruled out the possibility of providing additional assistance before an invasion. Those discussions are ongoing,” she said.

Last week, Biden told a press conference, “We’re actually going to increase the troop presence in Poland, Romania, etc., if in fact he moves.”

But PSAKI said Biden never ruled out sending additional US troops ahead of an invasion. “It’s part of our contingency planning,” she said.

The United States sent two arms shipments to Ukraine in the past week as part of recently directed security assistance to help bolster Ukraine’s military. NATO nations are also sending additional ships and fighter jets to Eastern Europe and putting forces on standby, NATO Secretary General Jens Stoltenberg said in a statement on Monday.

“NATO will continue to take all necessary measures to protect and defend all Allies, including strengthening the eastern part of the Alliance,” Stoltenberg said.

US and UK cut embassy staff in Kyiv

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

Ukrainian President Volodymyr Zelensky said in a video address on Monday that Ukrainian citizens had “no reason to panic” as authorities were “working to fully de-escalate the situation” in eastern Ukraine.

US officials still do not know what Russian President Vladimir Putin plans to do or if he has decided to invade Ukraine. But some officials who have seen the intelligence say there is evidence that Russia is planning to try to take Kiev and overthrow the government, as CNN has previously reported.

Britain’s Foreign Office said in a statement on Saturday that it had information that the Russian government was planning “to install a pro-Russian leader in Kiev as it plans to invade and occupy the Ukraine”.

Kirby said Monday that Russia was continuing to add “battalion battle groups” on the border with Ukraine and in Belarus. “Not only have they shown no signs of de-escalation, they actually add more force capacity,” he said.

Moscow denies plans to invade, accusing the United States and NATO of escalating tensions over their support for Ukraine. The Kremlin on Monday dismissed reports of plans to install a pro-Russian leader in Ukraine, calling it “hysteria”.

“Tensions are rising because of the concrete actions taken by the United States and NATO,” Kremlin spokesman Dmitry Peskov said. “I mean, the informational hysteria that we’re seeing. It’s generously framed by an enormous amount of misinformation, just lies and fakes.”

State Department officials told reporters on Sunday that the decision to downsize the embassy was not due to a change in threat levels facing U.S. personnel in the country. Officials said the decision to cut embassy staff and urge Americans in the country to leave was in part because State Department aid would be “severely affected” if there was a Russian military action in Ukraine.

Along with the downsizing of its embassy in Kyiv by the United States, the British Foreign Office also announced on Monday that some British embassy staff and dependents were being withdrawn in response to growing threats from the Russia.

The United States continues its diplomatic dialogue with Russia, but recent talks have yielded no breakthrough. Russia says the US and NATO must pledge never to admit Ukraine into NATO and withdraw military deployments from Eastern European countries, including Romania and Bulgaria . The United States has repeatedly said such requests are futile, although Secretary of State Antony Blinken said last week that the United States would respond in writing to Moscow’s demands after meeting with Russia’s business minister. foreigners Sergei Lavrov.

CNN’s Ellie Kaufman, Michael Conte, Kevin Liptak, Sharon Braithwaite, Anna Chernova and Katharina Krebs contributed to this report.