US President Barack Obama is set to lay out more of his plan for a stronger alliance with Vietnam, after scrapping an arms ban that was the last big hurdle between two countries drawn together by concern over China's military build-up.
The removal of a vestige of the Vietnam War suggests US worries about Beijing's building of man-made island in the South China Sea and deployment of advanced radars and missile batteries in the disputed region trumped concern about Vietnam's human rights record.
Washington had for years said a lifting of the ban would require concrete steps by Vietnam in allowing freedom of speech, worship and assembly, and releasing political prisoners.
In a joint news conference on Monday with his Vietnamese counterpart Tran Dai Quang, Obama said "modest" human rights improvements had been made and the decision to end the embargo was about the changing dynamic in ties and "not based on China".
The Global Times tabloid, run by the Chinese Communist Party's official People's Daily, said that was a lie and made a point of the what it said was a US willingness to relax standards on human rights for the sake of containing China.
The White House "is taking advantage of Vietnam to stir up more troubles in the South China Sea", it said.
Obama is to meet civil society representatives on Tuesday, among them dissidents, who may disagree with his arms ban decision. Some Vietnamese activists have expressed disappointment that Obama may have given away leverage with the communist leadership.
A US official, speaking on condition of anonymity, said there was evidence engagement had worked in nudging Vietnam to make concessions, like its "unprecedented" commitment to set up independent labour unions under a US-inspired Trans-Pacific Partnership trade deal.
In a statement late on Monday, Communist Party chief Nguyen Phu Trong spoke of the importance of building relations of mutual respect while "not interfering in each other's internal affairs".
Obama will give a speech in Hanoi about the development of relations since normalisation in 1995 and will champion his signature TPP, which would remove tariffs within a 12-nation bloc worth a combined US$28 trillion (NZ$41.50 trillion) of gross domestic product.
Vietnam's manufacturing and export-led economy is seen as the biggest TPP beneficiary. Annual US-Vietnam trade has swelled from US$450 million when ties were normalised to US$45 billion last year, and Washington is a big buyer of Vietnam's televisions, smartphones, clothing and seafood.
Obama will on Tuesday fly to Ho Chi Minh City, the country's commercial hub, which was called Saigon until North Vietnamese tanks rolled into the city in April 1975 to bring US-backed South Vietnam under communist rule.
He will meet young entrepreneurs at one of the co-working spaces that host Vietnam's budget tech startups, which have been receiving attention from angel investors and Silicon Valley funds.
Meanwhile the two countries on Tuesday signed an agreement allowing the US Peace Corps to work in the country for the first time.
The program, which is expected to begin over the next two years, allows Peace Corps volunteers to teach English in schools in the country's two largest cities, Hanoi and Ho Chi Minh City.
US Secretary of State John Kerry, who was present for the signing, said the agreement marked a further normalising of relations between the two nations.