A U.S. Marine Corps commander says a unit equipped with tanks, light armored vehicles and artillery will be sent to Bulgaria this fall as part of American plans to help reassure NATO allies worried by Russia's involvement in Ukraine.

Brig. Gen. Norman Cooling, deputy commander of U.S. Marine Corps Europe, told The Associated Press on Thursday that 155 Marines equipped with four Abrams tanks, six light armored vehicles and three howitzers are scheduled to be in place at the Novo Selo training area by early September.

The Marine unit will train with Bulgarian, Romanian and other allied forces over the next 18 months.

U.S. Defense Secretary Ash Carter said this week that more American military equipment would be positioned in Estonia, Lithuania, Latvia, Bulgaria, Romania, Poland and Germany.