Vietnam's President Truong Tan Sang and US President Barack Obama have met for landmark talks in Washington.
Mr Sang is only the second Vietnamese president to have
embarked on a White House visit since the two countries resumed ties in
1995.The talks on Thursday focused on a trade pact called the Trans-Pacific Partnership and human rights issues.
Relations have been improving between the former foes, amid the US strategic "pivot" to Asia.
"We all recognise 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," Mr Obama said.
Human rights activists, however, have criticised the visit, pointing out that Vietnam has been stepping up a crackdowns against government critics.
After the meeting, Mr Obama told reporters that both countries were "committed to the ambitious goal of completing [the Trans-Pacific Partnership] agreement before the end of the year".
The pact "will be an extraordinarily ambitious effort to increase trade, commerce and transparency in terms of commercial relationships throughout the Asian Pacific region," he added.
'Differences'
Vietnamese-American protestors called for a greater focus on human rights
The two leaders also discussed "the challenges that all of us face when it comes to issues of human rights", Mr Obama said."We emphasised how the United States continues to believe that all of us have to respect issues like freedom of expression, freedom of religion, freedom of assembly," he said.
Truong Tan San said: ""We touched upon the war legacy issues including human rights which we still have differences on."
However, he said these issues should not prevent closer links between the two countries, and said he had invited Mr Obama to visit Vietnam.
Correspondents say at least 38 activists, including bloggers, have been arrested for anti-state activities in Vietnam this year.
Truong Tan Sang was elected to the largely ceremonial post of president in July 2011 by parliament.
He is a former mayor and Communist Party chief who was jailed by the US-backed South Vietnamese government in the early 1970s.
The last Vietnamese president who made an official visit to the US was Nguyen Minh Triet in 2007.
The Vietnam war, which lasted from 1955 to 1975, killed an estimated 58,000 US soldiers and three million Vietnamese.
This visit marks an important step in Vietnam-US relations, especially when Vietnam is seeking to safeguard its interests in the South China Sea, says the BBC's Nga Pham in Bangkok.
Vietnamese officials have repeated many times that Hanoi is looking to upgrade the relationship with Washington to a strategic partnership in order to boost confidence and co-operation, our correspondent adds.
Vietnam is embroiled in a dispute with China over islands in the South China Sea known in China as Xisha but the Paracels elsewhere.
Beijing has controlled them since a short war with South Vietnam in 1974.