US President George W Bush has stressed the importance of a free society to Vietnam's President, Nguyen Minh Triet, during landmark talks in Washington.
Mr Triet said there had been a direct and open exchange of views
Mr Bush said the two men had a "frank and candid discussion" about democracy and human rights at the White House.
Mr Triet is making the first visit to the US by a Vietnamese head of state since the Vietnam War ended in 1975.
Critics of his government had urged Mr Bush before the meeting to focus on Vietnam's poor human rights record.
Members of Congress and Vietnamese exiles said restrictions against dissent within Vietnam had been tightened recently.
During the meeting, hundreds of protesters outside the White House called for the release of political prisoners and jailed Catholic priests.
'Direct and open'
After the meeting, Mr Bush said he had raised the issue with his Vietnamese counterpart.
"Societies are enriched when people are allowed to express themselves freely or worship freely," he said.
"In order for relations to grow deeper, it's important for our friends to have a strong commitment to human rights and freedom and democracy," he added.
Mr Triet said there had been a "direct and open exchange of views, especially on matters relating to religion and human rights".
But in an interview with the Associated Press after the meeting, he said that Vietnam did not need to improve its human rights record.
"It's not a question of improving or not," Mr Triet said.
"Vietnam has its own legal framework, and those who violate the law will be handled."
Mr Triet had attempted to focus on the trade ties between his country and the US, Vietnam's biggest export market, before the talks.
Trade between the two countries reached $10bn (£5bn) last year.
Some Vietnamese-Americans are angry about the visit
Accompanied by a delegation of more than 100 business leaders, Mr Triet signed a trade and investment agreement with Washington on Thursday.
But during a later meeting with US politicians, Mr Triet was repeatedly asked about claims by human rights groups that his government had repressed internal opposition.
A number of prominent pro-democracy activists, including priests and lawyers, have been sentenced to long jail terms in the past year.
The release of at least two activists in recent days has been seen as a goodwill gesture.
But observers say that, with the prosecution of dissidents and new rules banning civil servants from talking to the media, there are few signs that closer ties with the US will produce any tangible human rights benefits.