This story, which was originally published Wednesday, May 18, has been updated with confirmation that President Barack Obama has lifted the arms embargo.

WASHINGTON — The United States has fully lifted its ban on weapons sales to Vietnam, President Barack Obama announced on Monday during a visit to Hanoi, ending a decades-old embargo on the one-time enemy.

Obama was keen to separate the decision to allow arms sales to the communist nation from shared concerns over China's military build-up in the disputed South China Sea.

"The decision to lift the ban was not based on China... but on our desire to complete what has been a lengthy process moving towards normalization with Vietnam," Obama said at a joint press conference alongside his Vietnamese counterpart President Tran Dai Quang.

"At this stage, both sides have developed a level of trust and cooperation including our militaries," the US leader added.

Vietnam's Prime Minister Nguyen Xuan Phuc (3rd R) and his entourage hold official talks with US President Barack Obama (not pictured) at Phuc's cabinet office in Hanoi in May 23, 2016. Obama praised
Vietnam's Prime Minister Nguyen Xuan Phuc (3rd R) and his entourage hold official talks with US President Barack Obama (not pictured) at Phuc's cabinet office in Hanoi in May 23, 2016. Obama praised "strengthening ties" between the United States and Vietnam at the start of a landmark visit on May 23, as the former wartime foes deepen trade links and share concerns over Chinese actions in disputed seas. / AFP / POOL / HOANG DINH NAM (Photo credit should read HOANG DINH NAM/AFP/Getty Images)

Vietnam's Prime Minister Nguyen Xuan Phuc holds official talks with US President Barack Obama.

Photo Credit: Hoang Dinh Nam/AFP/Getty Images

In the weeks before Obama's trip, regional observers were tracking carefully what would happen if the president did lift the embargo.

In 2014, the Obama administration announced a partial lift of the weapons ban, with a limited focus on maritime security assets. However, there is a belief that the administration may look to make a splash during the president’s visit to the region and remove the export ban as a whole.

Such a move has support from Defense Secretary Ash Carter, who said in an April 28 hearing in front of the Senate Armed Services Committee that he would backed the end of the ban. It also has support in the form of SASC chairman Sen. John McCain, who has been vocal in his desire to see more equipment flow toward Vietnam.

But news that the Obama administration was considering ending the full export ban, first reported by Foreign Policy magazine, quickly raised concerns on Capitol Hill, with the office of Sen. Bob Corker indicating a need for review and consideration before jumping on board.

Corker's restraint is notable for two reasons: one, as the chair of the Senate Foreign Relations Committee, he has immense power over foreign weapon sales and two, he backed the 2014 decision that partially lifted the ban on weapon exports to Vietnam.

Phuong Nguyen of the Center for Strategic and International Studies says the issue on the Hill centers on human rights. While Vietnam has talked about taking steps forward in that realm, skepticism and concerns remain in Congress about how offensive weapons might be used against Vietnam's own citizens.

"Their concerns are valid to an extent. You wouldn't want to lift the ban on a regime that could buy arms and potentially use them for human rights violations," Nguyen said. "But that doesn't necessarily apply to Vietnam, because it doesn't make sense that the US gives support and training for Vietnam's military to take part in peacekeeping operations under the UN, and then maintains a ban on that military. And in Vietnam it's not the military with a human rights problem."

Because of the human rights concerns, Nguyen warned that getting congressional buy-in on a full export control lift may be difficult.

"It's really a mixed bag because even people who supported the lift in 2014 don't necessarily support the full lift now. So it's really hard to tell now," she said.

David McKeeby, a spokesman for the State Department's Bureau of Political-Military Affairs, said in a statement that human rights remains "an essential element of our policy with Vietnam" and noted that all weapon deals are judged on a case-by-case basis, but he would not comment on the potential for the arms embargo to be ended.

Limited Interest from Vietnam

Roughly a year ago, Carter traveled to Vietnam and announced a new military-economic partnership.

The agreement called for the two sides to "expand defense trade between our two countries, potentially including cooperation in the production of new technologies and equipment, where possible under current law and policy restrictions."

At the time, Vietnam was buying 90 percent of its military equipment from Russia, US officials said. If the Obama administration could change that, it would have the dual benefits of breaking ties between Vietnam and the Putin administration at a time of tensions between the US and Russia, while also strengthening a potential check on Chinese ambitions in the region.

But a year later, little has come out of the agreement, despite the US Embassy in Hanoi holding workshops for US defense firms and representatives of Vietnam's military and government, according to Nguyen.

"The US expected Vietnam to show more interest" following both the 2014 partial lift and the new agreement, she said, "and they are interested, but they weren't going to be rushed into making a decision."

That creates a potential Catch-22 situation, Nguyen said, "with the ban in place [Vietnamese officials] may not have incentive to express interest, and then people here say 'why lift the ban if there is no interest?'"

Also creating roadblocks: Like many developing nations, Vietnam is less interested in procuring technology than in building its own nascent military-industrial base.

"They are interested in working together on defense trade but they're not interested in just buying," Nguyen said. "They want the US to help build up their defense industry — that's their objective in working with the US."

However, some short-term needs must be filled by American industry. A big focus for Vietnam at a time when China is laying claim to the South China Sea is protecting its coastlines. To Doug Barrie, senior analyst at the International Institute for Strategic Studies, that means a wide range of opportunities.

"I'd expect maritime patrol and anti-submarine warfare to be high on the shopping list — second-hand P-3 or even the P-8 were it to be made available, although the latter is quite a leap," Barrie said. "In terms of combat air, the air force's Su-22s and MiG-21s need to be replaced so a modern fighter to complement the Su-30 is likely to be sought. Recapitalizing the rotary transport fleet is also another possibility."

However, Nguyen believes Vietnam will look to move somewhat slowly in order to not directly antagonize its much larger neighbor.

"They are not going to get American fighter jets anytime soon," Nguyen noted. "They want to move incrementally so Beijing doesn't see it as a threat that needs to be responded to."

Agence France-Presse contributed to this story.

Twitter: @AaronMehta