The military exercise comes despite China’s irritation following weeks of fiery exchanges between the communist neighbors over disputed areas of the South China Sea.

U.S. and Vietnamese officials have stressed that the seven-day ship visit and naval training are part of routine exchanges planned long before tensions began flaring between China and Vietnam in late May. China has criticized the port call as inappropriate, saying it should have been rescheduled due to the ongoing squabble.

The U.S. visit, however, did send a message that the Navy remains a formidable maritime force in the region and is determined to build stronger military ties with smaller Southeast Asian countries.

"We’ve had a presence in the Western Pacific and the South China Sea for 50 to 60 years, even going back before World War II," Rear Adm. Tom Carney, who’s leading the naval exchange, told reporters. "We will maintain a presence in the Western Pacific and the South China Sea as we have for decades, and we have no intention of departing from that kind of activity."

He spoke on the pier in central Danang, once home to a bustling U.S. military base during the Vietnam War, in front of the diving and salvage ship USNS Safeguard. American and Vietnamese flags flapped in the steamy air from the ship, and two guided missile destroyers — USS Chung-Hoon and USS Preble — were visible off the coast.

The two navies will hold exchanges involving navigation and damage control along with dive and salvage training. No live-fire drills will be conducted.

Vietnam and China last month both announced their navies held such maneuvers individually in the South China Sea after relations hit a low point when Hanoi twice accused Beijing of hindering oil exploration within Vietnam’s economic exclusive zone.

China responded that Vietnamese boats had endangered Chinese fishermen in a different area near the contested resource-rich Spratly islands, claimed all or in part by both nations and several others.

Tempers appeared to be cooling after Chinese and Vietnamese officials met last month and announced they would work to negotiate a peaceful resolution. But Vietnamese state-run media and a border official on Wednesday accused armed Chinese soldiers of attacking and chasing a Vietnamese fishing boat near the disputed Paracel islands claimed by both countries.

The Philippines has also recently sparred with China, alleging similar interference with its energy exploration efforts in the South China Sea. The U.S. last month conducted similar joint naval exercises that included live-fire drills with the Philippines, a treaty ally.

On Monday in Beijing, top Chinese Gen. Chen Bingde criticized his U.S. counterpart for going forward with the exercises in Vietnam and the Philippines, calling it bad timing in light of the ongoing spats. Adm. Mike Mullen, chairman of the U.S. Joint Chiefs of Staff, defended the decision saying the exchanges were pre-planned.

"I don’t know when an appropriate time would be for these kind of activities, which are designed to promote friendship and cooperation," Carney said from the Vietnam pier. "But I don’t think there’s ever a bad time to do those kind of activities."

Washington has said that the South China Sea, home to major shipping lanes, is in its national interest. China, which has an expanding maritime influence, has designated the area as a core interest — essentially something it could go to war over. Worried smaller neighboring countries have looked to the U.S. to maintain a strong presence in the region.

"The U.S. has made its point and will continue to do so if pressed, but does not appear to be looking for a fight with Beijing on this issue," said Ralph Cossa, president of Pacific Forum CSIS, a Hawaii-based think tank. "It is not likely to heed or back down as a result of Chinese ‘warnings,’ however, which will likely make Washington feel more compelled to respond."

The current U.S. visit to Vietnam involves about 700 sailors and builds on the first postwar port call in 2003 made to the former Saigon, now called Ho Chi Minh City. Since then, military relations have continued to grow with high-level defense visits and exchanges.

The two sides recently began working together to clean up dioxin contamination from the defoliant Agent Orange. It was mixed and stored at the U.S. air base in Danang and remains one of the lasting legacies of the Vietnam War that killed some 58,000 Americans and an estimated 3 million Vietnamese.

The war ended in 1975 when U.S.-backed South Vietnam fell to northern communist forces and the country was reunified. The U.S. and Vietnam shook hands in 1995 and established diplomatic relations, signing a landmark trade deal six years later.

Today, the U.S. is Vietnam’s top export market, while Americans are among the country’s leading foreign investors.