US President Barack Obama on Thursday called on Vietnam's leader to improve on human rights but the former enemy nations pledged to work together on trade and tensions with China.
President Truong Tan Sang, only the second Vietnamese head of state to visit Washington since the normalization of relations in 1975, was jeered by hundreds of Vietnamese Americans, many waving the flags of the former Saigon regime and chanting slogans that were occasionally audible inside the White House.
But the two leaders looked upbeat during their meeting at the Oval Office, with Obama saying that Sang showed him a letter written by revolutionary Ho Chi Minh to former US president Harry Truman that voiced hope for cooperation, two decades before their traumatic war.
"We all recognize the extraordinarily complex history between the US and Vietnam. Step by step we have been able to establish a degree of mutual respect and trust," Obama said.
Obama said he had nevertheless pressed Sang on human rights, a top concern of US lawmakers, who have voiced alarm at the detention of dozens of bloggers and government critics.
"The United States continues to believe that all of us have to respect issues like freedom of expression, freedom of religion, freedom of assembly," Obama told reporters at the Oval Office with Sang at his side.
"We had a very candid conversation about both the progress that Vietnam is making and the challenges that remain," he said.
In a joint statement, Sang promised that Vietnam would sign the UN Convention Against Torture by the end of the year.
Vietnam is one of the few holdouts from the treaty, which critics say is ineffective and includes even China, which is often faulted on human rights.
The statement also pledged mutual respect for each other's political systems, 38 years after Vietnam's communists captured the former Saigon.
Several lawmakers have accused Obama of merely mentioning human rights and said he should have made progress a condition for further improvements in relations.
Sang, who acknowledged "differences" between the two countries on human rights, said Obama had promised to visit Vietnam by the end of his second term.
Obama, who would be the third successive US president to visit Vietnam, is expected in the region in October for summits in Bali and Brunei.
Vietnam has sought stronger ties with the United States at a time of rising tension with China, which Hanoi accuses of assertive claims to disputed territories.
Sang and Obama, in the statement, called for "the settlement of disputes by peaceful means" and renewed support for a code of conduct to manage mishaps.
The United States has stepped up military ties with Vietnam but has held off on offering "lethal" weapons due to rights concerns.
Obama welcomed Vietnam's upcoming entry into UN peacekeeping operations and called for more "non-traditional" security cooperation, including in disaster relief.
Obama has increasingly put a focus on Southeast Asia, seeing the region as economically vibrant, largely US-friendly and neglected in the past by US policymakers.
Sang is the fourth Southeast Asian leader to visit the White House this year.
As part of its so-called Asia pivot, the United States has championed the Trans-Pacific Partnership, which aims to create a vast free trade zone.
Twelve nations are taking part, including Vietnam and most recently Japan, meaning that the pact would cover 40 percent of the world economy.
Obama and Sang recommitted to completing negotiations by the end of the year, but Obama acknowledged it was an "ambitious goal."
US labor unions have criticized Vietnam's participation, saying it does not protect workers adequately enough to join a free trade zone with developed nations such as the United States, Australia and New Zealand.
Protesters outside the White House held up signs saying "No trade without human rights," and "Communist - Go Home."
"Okay, you can invite him, but you have to put on the table pressure to push the Vietnamese communists to comply with international law and human rights," said activist Huu Dinh Vo.
Several other Vietnamese Americans meanwhile carried banners that denounced not Sang, but China, over its territorial claims.
Sang, speaking in the Oval Office, thanked the United States for welcoming Vietnamese Americans who are becoming "more and more prosperous and successful."
Sang voiced hope that the 1.7 million-strong Vietnamese American community would start "contributing more and more to the friendship between our two countries."