USS Carl Vinson arrives in Vietnam

A US aircraft carrier arrived in Vietnam on Monday for the first time since the end of the Vietnam War, dramatically underscoring the growing strategic ties between the former foes at a time when China's regional influence is rising.

The grey and imposing silhouette of the USS Carl Vinson could be seen on Monday morning from the cliff tops just outside the central Vietnamese city of Danang, where the 103,000-tonne carrier and two other U.S. ships begin a five-day visit.

"The visit marks an enormously significant milestone in our bilateral relations and demonstrates U.S. support for a strong, prosperous, and independent Vietnam," Daniel Kritenbrink, the U.S. ambassador to Vietnam, said in a statement.

"Through hard work, mutual respect, and by continuing to address the past while we work toward a better future, we have gone from former enemies to close partners."

The arrival of the Vinson marks the biggest U.S. military presence in Vietnam since 1975 - but it also illustrates Hanoi's complex and evolving relationship with Beijing over the disputed South China Sea.

Vietnamese envoys had been working for months to ease the concerns of their giant Chinese neighbour over the visit and the prospect of broader security cooperation between Hanoi and Washington, according to diplomats and others familiar with the talks.

U.S. carriers frequently ply the South China Sea in a rising pattern of naval deployments, and are now routinely shadowed by Chinese naval vessels, naval officers in the region say.