The United States says some 750 U.S. Army tanks, helicopters, and other equipment have arrived in Riga, Latvia.
The Pentagon said the March 9 deployment was a part of the U.S. military's Operation Atlantic Resolve aimed at demonstrating commitment to NATO allies in light of what members of the alliance see as Russia's increasingly aggressive attitude.
U.S. General John O'Connor told AFP the deployment would "demonstrate resolve to President (Vladimir) Putin and Russia that collectively we can come together."
The Defense Department said some 3,000 members of a 3rd Infantry Division brigade combat team will begin flowing into the region next week as part of a three-month deployment.
The unit will participate in multinational training missions with NATO partners in Estonia, Latvia, and Lithuania.
It will take over responsibility for the training mission from the U.S. 2nd Cavalry Regiment, which will depart this month.