For the first time since the Vietnam War, a U.S. Navy aircraft carrier is visiting a Vietnamese port, seeking to bolster both countries' efforts to stem expansionism by China in the South China Sea.

Monday's visit by the USS Carl Vinson brings more than 6,000 crew members to the central coastal city of Danang, the largest such U.S. military presence in Vietnam since the Southeast Asian nation was unified under Communist leadership after the war ended in 1975.

The visit comes amid China's increasing military buildup in the Paracel islands and seven artificial islands in the Spratlys in maritime territory also claimed by Vietnam. China claims most of the South China Sea and has challenged traditional U.S. naval supremacy in the western Pacific.