President Joe Biden ordered U.S. troops already based in Europe to shore up the defenses of nations bordering Ukraine.
Biden directed Secretary of Defense Lloyd J. Austin III to move forces within the U.S. European Command's area of operations to the Baltic Republics, Poland and Ukraine's southeastern flank.
The forces will move within a week, DOD officials said.
The deployment follows Russia's renewed invasion of eastern Ukraine and Russian President Vladimir Putin's mobilization of forces all along the borders of Ukraine.
Austin has ordered an infantry battalion task force of about 800 soldiers to deploy from Italy to the Baltic region. He also approved the movement of up to eight F-35 Lightning II aircraft from Germany to operating locations on NATO's eastern flank.
Twenty AH-64 Apache attack helicopters will also deploy from Germany to the Baltic region and 12 Apache helicopters will move from Greece to Poland.
"These additional personnel are being repositioned to reassure our NATO allies, deter any potential aggression against NATO member states, and train with host-nation forces," DOD officials said in a written statement. All forces are under the command of Air Force Gen. Tod D. Wolters, the commander of U.S. European Command.
Officials said the moves are temporary.
These moves are the latest in a series designed to reassure the frontline states. The United States sent 1,000 soldiers from a Stryker squadron from Germany to Romania. An 82nd Airborne Division infantry brigade combat team will be deployed to Poland from Fort Bragg, North Carolina. Company-sized Stryker units will deploy to Hungary and Bulgaria.
In addition, Austin ordered 8,500 service members to a heightened state of readiness should NATO activate its Rapid Reaction Force.
Overall, there are about 90,000 U.S. service members based in Europe.