The Pentagon will send an additional 3,000 troops from the 82 Airborne Division to Europe in the coming days as the prospect for a Russian invasion of Ukraine appears to grow.

"As we've said before, we are in the window when an invasion could begin at any time should Vladimir Putin decide to order it," said Jake Sullivan, President Biden's National Security Advisor.

White House national security adviser Jake Sullivan speaks during the daily briefing at the White House in Washington, Monday, Aug. 23, 2021.

White House national security adviser Jake Sullivan speaks during the daily briefing at the White House in Washington, Monday, Aug. 23, 2021. (AP Photo/Susan Walsh)

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Sullivan affirmed that America is "also ready to respond to decisively," alongside foreign allies "should Russia choose to take military action."

The move from the Biden administration was announced by the Department of Defense over the weekend, but an official confirmed the deployment to Fox News on Friday.

"At the direction of the President, Secretary Austin today ordered to Poland the remaining 3,000 soldiers of the 82nd Airborne Infantry Brigade Combat Team based at Fort Bragg, N.C.," the official said. "These troops will depart Fort Bragg over the next couple days. They are expected to be in place by early next week."

This group of paratroopers, the second batch of soldiers being sent to Poland, will join the 1,700 soldiers and key enablers that Austin ordered there on February 2nd.

US Army General Christopher Donahue, left, commanding general of the 82nd Airborne Division, and Polish General Wojciech Marchwica speak to journalists after unloading vehicles from a transport plane arriving from Fort Bragg at the Rzeszow-Jasionka airport in southeastern Poland, on Sunday, Feb. 6, 2022.

US Army General Christopher Donahue, left, commanding general of the 82nd Airborne Division, and Polish General Wojciech Marchwica speak to journalists after unloading vehicles from a transport plane arriving from Fort Bragg at the Rzeszow-Jasionka airport in southeastern Poland, on Sunday, Feb. 6, 2022. (AP Photo)

"Nearly two-thirds of this first tranche has already arrived," the official said, noting that they are commanded by Maj. Gen. Christopher Donahue.

"All told, these 5,000 additional personnel comprise a highly mobile and flexible force, capable of multiple missions," the official added. "They are being deployed to reassure our NATO allies, deter any potential aggression against NATO’s eastern flank, train with host-nation forces, and contribute to a wide range of contingencies. They will report to Gen. Tod Wolters, Commander, U.S. European Command."

The official said the "additional deployments are temporary in nature" and are "meant to supplement for a brief time the more than 80,000 U.S. troops already in Europe on rotational and permanent orders."

Secretary of Defense Lloyd Austin listens to a question during a media briefing at the Pentagon, Wednesday, Aug. 18, 2021, in Washington.

Secretary of Defense Lloyd Austin listens to a question during a media briefing at the Pentagon, Wednesday, Aug. 18, 2021, in Washington. (AP Photo/Alex Brandon)

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In addition, Defense Sec. Lloyd J. Austin III will temporarily reposition 160 troops who are training Ukraine's military out of the country. 

According to an article shared to the department's website, "A total of 160 members of the Florida National Guard have been deployed to Ukraine since late November training and advising and mentoring Ukrainian armed forces."

Fox News' Jennifer Griffin and Lucas Tomlinson contributed to this article.