U.S. Marines accompanied by tanks, artillery, and light-armored reconnaissance vehicles have arrived in Bulgaria, part of a plan to train with allies to improve weapons skills and anti-armor tactics.

The U.S. Marine Corps Forces said Tuesday some 160 Marines accompanied the tanks and artillery, which is traveling to the Novo Selo Training Range, a major military base in eastern Bulgaria, as part of the Black Sea Rotational Force. They will stay initially for three six-month rotations. No further details were immediately available.

The Black Sea Rotational Force is a semi-annual rotation of Marines and sailors under the U.S. European Command. It is based at the Mihail Kogalniceanu base in Romania near the Black Sea port of Constanta.