The visit comes as the US and Vietnam look to deepen ties amid concerns about China’s growing regional strength.

The port call comes as the US and Vietnam look to deepen ties, 10 years after signing their “comprehensive partnership”, amid shared trade ties and concerns about China’s growing strength in the region.

A Chinese survey vessel, multiple coast guard ships and fishing boats operated for several weeks in Vietnam’s exclusive economic zone in the South China Sea, prompting Vietnam’s foreign ministry to demand that they leave.

The boats eventually left in early June.

China claims almost all the South China Sea under its so-called nine-dash line, deploying ships and building artificial islands and military facilities on reefs and outcrops. It has also ignored a 2016 international court ruling that the nine-dash line had “no legal basis“.

Besides Vietnam, the Philippines, Malaysia and Brunei also claim parts of the sea.

“The visit gives that message that Vietnam is continuing to balance against China by improving its security relationship with the US, and with other outside powers,” Nguyen The Phuong, a PhD candidate in maritime security at the University of New South Wales Canberra, told the AFP news agency.

The visit of the nuclear-powered USS Ronald Reagan is only the third by a US aircraft carrier since the end of the Vietnam War and follows the arrival of Indian naval ships in Danang last month, as well as a port call by Japan’s largest warship in Cam Ranh, a city on the southeastern coast, earlier this week.

The US aircraft carrier is expected to remain in Danang until June 30.

Strong bilateral ties between the US and Vietnam are key for Washington if it wants to remain the dominant power in the region, Phuong said.

“The US hopes that by sending one of their most formidable naval assets, they will have a trusted and reliable partner in Vietnam,” he said.

The US Secretary of State Antony Blinken visited Hanoi in April and made it clear he wanted to upgrade diplomatic ties.

The first US aircraft carrier to visit Vietnam was the USS Carl Vinson in 2018, with the USS Theodore Roosevelt stopping in 2020 to mark 25 years since the end of the  Vietnam War.