Twelve U.S. Air Force A-10 Thunderbolt IIs have been deployed for months of military exercises involving the U.S. and Romanian air forces designed to reassure eastern Europeans who fear Russian influence in the region.

Some 350 U.S. and 300 Romanian troops are taking part in the "Atlantic Resolve" exercises that end in July.

U.S. Lt.Gen. Darryl Roberson, 3rd Air Force and 17th Expeditionary Air Force told reporters Thursday that the exercises would allay fears of NATO allies about Russia amid the Ukraine crisis.

"Intimidating actions ... have created significant distress among east Europeans and resurrected thoughts of a not too distant past," he said.