NATO's supreme commander in Europe says a convoy of U.S. troops crossing eastern Europe is a way of reassuring allies of the military alliance's support and of practicing little-used skills.

Gen. Philip Breedlove said Tuesday during a visit to Bucharest that the exercise tested many things that "hadn't been done for a long time in NATO....like multiple border crossings and which bridges are capable of handling the vehicles."

The "Dragoon Ride" convoy started last week from Estonia and passed through Latvia, Lithuania and Poland, before entering the Czech Republic on a return journey to a German base.

The soldiers took part in the Atlantic Resolve exercise intended to demonstrate NATO's readiness to defend its members.