WASHINGTON » President Barack Obama appears poised to begin selling weapons to an old enemy and a new friend: Vietnam.

Obama, who will embark this weekend on his first trip to the Communist country, is weighing an end to a United States’ ban on selling weapons that started in 1975 at the close of the Vietnam War, which left nearly 60,000 Americans dead and scarred.

Vietnam has long sought an end to the moratorium. But the request took on a more urgent tone in recent years after its neighbor, China, repeatedly threatened or attacked ships in the disputed waters of the South China Sea and started picking territorial fights with Vietnam, the Philippines and Japan.

Obama’s possible action, which lawmakers and U.S.-Vietnamese experts say could occur sometime this year, would cap a stunning shift following the United States’ failed intervention in Vietnam in the 1960s and 1970s.

“This is one of the last vestiges of a bygone era,” said Joseph Liow, a senior fellow at the Center for East Asian Policy at the center-left Brookings Institution. “The symbolism is more important than the shopping list.”

Vietnam has not given the United States a specific wish list of weapons. Experts say Hanoi could be looking for warships, missiles and radar, and surveillance and communications equipment. Examples include Lockheed’s P-3 Orion and C-130 Hercules, both assembled in Georgia, or Boeing’s P-8 Poseidon, which is assembled in Washington state. The military aircraft could help track Chinese ships and submarines.

The U.S. has not sold lethal weapons to Vietnam since communists took control of the country at the end of the Vietnam War. President Ronald Reagan officially prohibited arms sales in 1984.

“Vietnam believes that this element of barrier of the past should be removed to reflect our full normalization of relations started two decades ago, and the current level of our comprehensive partnership,” Pham Quang Vinh, the Vietnamese ambassador to the United States, said recently in Austin.

The country’s main source of weapons now is Russia, which has provided Vietnam with Kilo-class submarines and Sukhoi fighter jets, and would likely remain a cheaper and more efficient supplier.

In recent years, the U.S. and Vietnam have engaged in increasingly close political, economic and military ties, though several disagreements remain over American service members missing in action and the U.S. military’s use of hazardous chemicals, including Agent Orange, during the war.

Former President Bill Clinton announced the formal normalization of diplomatic relations between the U.S and Vietnam in 1995. Clinton in 2000 became the first sitting president to visit Vietnam since U.S. troops left the country and the first ever to visit Hanoi in the former North Vietnam.

George W. Bush also visited, in 2006.

Obama hosted the head of Vietnam’s ruling communist party at the White House last year. After his three-day visit to Vietnam, he will attend a meeting of the Group of Seven industrialized nations in Japan and visit Hiroshima, the site of the world’s first atomic bombing.

Obama can lift the arms embargo to Vietnam — or parts of it — without congressional approval. But lawmakers would need to sign off on individual sales.

He removed a piece of the ban in late 2014, allowing the sale of equipment for “maritime security purposes.” The State Department did not respond to questions about specific weapons except to say each request is reviewed on a case-by-case basis. But, according to Capitol Hill staffers and experts, Vietnam has made no major weapons purchase since 2014.

Several Vietnamese groups and U.S. lawmakers are pushing Obama to completely lift the weapons ban because of China’s actions.

“They sunk a Vietnamese vessel a couple years ago. There is a history, a 2,000-year history, of occupation of Vietnam,” Sen. John McCain, R-Ariz., a former prisoner of war, said in an interview. “I believe that Chinese behavior warrants us assisting them in obtaining the ability to defend their rights as a nation.”

Other lawmakers and human rights groups oppose the change, saying it would eliminate the leverage the U.S. has used to push Vietnam to change its still-poor human rights practices.

“Vietnam hasn’t delivered,” said John Sifton, Asia policy director at Human Rights Watch. “It really doesn’t make sense to give them a reward they don’t deserve.”

The Senate Armed Services Committee recently approved language that encourages both removing the ban and establishing a review process for future sales to ensure that Vietnam continues to make progress on human rights.

Defense Secretary Ash Carter spoke of his approval of the change recently while testifying on Capitol Hill.

Secretary of State John Kerry, himself a prominent Vietnam War veteran, has not been as vocal. But Daniel Russel, assistant secretary of state for East Asia and the Pacific, talked about what’s at stake on a recent visit to Vietnam along with Tom Malinowski, the administration’s top human rights envoy.

“Many countries have expressed deep concern about some of the behavior of China, a major claimant, in reclaiming land and conducting large-scale construction and in militarizing outposts in the South China Sea,” Russel said.

Vietnam has criticized China for threatening its fishing boats, engaging in exploratory drilling and embarking on a massive land reclamation program, all in the South China Sea.

Arms sales to Vietnam would come after a gradual increase in U.S. interaction and aid to Vietnam over the years.

In 2013, the U.S. announced it would provide $18 million to Vietnam to help buy coast guard patrol vessels for the South China Sea. More recently, Congress authorized $450 million over five years to provide equipment, supplies and training to South East Asian nations, including Vietnam, to deal with maritime sovereignty issues.

Still, any decision to sell weapons to Vietnam is expected to anger China, which described Obama’s partial lifting of the ban in 2014 as interfering in the region’s balance of power.

“It’s safe to say China will preempt and react negatively,” said Michael Green, senior vice president for Asia at the Center for Strategic and International Studies. “It’s been pretty much the M.O. for Beijing to interject in arms decisions by other countries that would move them closer to the U.S.”

Curtis Tate contributed to this report.