A U.S. aircraft carrier will visit Vietnam next year, the Pentagon said in a statement on Tuesday, in a sign of improving relations between the two countries, according to Reuters.

U.S. Defense Secretary Jim Mattis and Vietnamese Minister of National Defense Ngo Xuan Lich (photo) agreed to the carrier’s visit in a meeting at the Pentagon earlier this week the statement said.

The carrier to make the visit was not identified. It is believed to be the first visit by a U.S. aircraft carrier since the Vietnam War ended in 1975.

President Donald Trump discussed the possibility of a U.S. carrier visit with Vietnamese Prime Minister Nguyen Xuan Phuc when the two leaders met in May at the White House, Vietnam's government said at the time. Relations between the United States and Vietnam have improved amid shared concerns about China's expansive claims in the South China Sea.

The United States and Vietnam have found common ground in recent years over China’s assertive claims over much of the South China Sea. Vietnam and other Southeast Asian countries hold counterclaims on islands in the area, which is believed to hold reserves of untapped petroleum and possibly valuable ores.

While the U.S. maintains no claims of sovereignty over any part of the South China Sea, officials are concerned that China could eventually dictate which vessels would be allowed to sail or fly there.

U.S. Pacific Fleet ships routinely patrol the South China Sea, engaging in so-called freedom of navigation operations near disputed islands occupied or militarized by China.

Vietnam and China have engaged in diplomatic skirmishes over attempted petroleum exploration in the waters near the Vietnam coast.

The U.S. recently transferred a former Coast Guard cutter to Vietnam to help the country improve its maritime law-enforcement, the Pentagon said.

The U.S. signed a peace accord with North Vietnam in 1973 after almost a decade of war during which America was allied with South Vietnam.