HANOI (Reuters) - The United States has delivered six patrol boats worth $12 million to Vietnam’s Coast Guard, the U.S. embassy in Hanoi said on Monday, amid warming ties between the former foes.

The vessels are in addition to another twelve “Metal Shark” patrol boats and a high-endurance cutter provided to Vietnam by the United States in the last two years.

“Delivering these patrol vessels represents deepening U.S.-Vietnam cooperation in the areas of maritime law enforcement, maritime search and rescue, and maritime humanitarian assistance operations within Vietnam’s territorial waters and exclusive economic zone,” the embassy said in a statement.

Since emerging from decades of diplomatic isolation in the early 1990s, Vietnam has been eager to improve ties with large powers and the region to help balance its historically thorny relations with its giant neighbor, China, which confronts Vietnam over claims to the South China Sea.

An Indian Coast Guard vessel docked at a port in the central city of Danang for a four-day visit on Monday, Vietnamese state media reported, amid strengthening military ties between the two countries.

China claims 90 percent of the potentially energy-rich South China Sea, but Brunei, Malaysia, the Philippines, Taiwan and Vietnam also lay claim to parts of it, through which about $3 trillion of trade passes each year.

U.S. President Donald Trump used a meeting with Vietnamese officials to pitch arms exports from the United States, ahead of his Hanoi summit with North Korean leader Kim Jong Un in February.

The Metal Shark “45 Defiant” patrol boat is manufactured in the United States by Gravois Aluminium Boats LLC.

It can reach speeds of up to 50 knots (93 km per hour) and is suited for both inland and offshore use, according to the manufacturer’s website.