
Charlie Ly, a prominent member of the Vietnamese-American community in Philadelphia, Pennsylvania, had been trying to leave Vietnam since July 24.
"As far as I know, Charlie Ly has left Vietnam," government spokesman Le Dung said a press conference.
The US embassy in Hanoi confirmed Ly had boarded a flight to the United States Thursday morning.
A US-based Vietnamese exile organisation called the Democratic Party of Vietnam issued a press release Monday saying Ly had come to Vietnam July 14 to visit "family and friends" but had been prevented from leaving the country 10 days later by Vietnamese authorities.
Ly was called in for repeated interviews by police in Ho Chi Minh City. The Democratic Party of Vietnam said police demanded he sign a statement saying he had attempted to meet with a Democratic Party member in Vietnam and promising to refrain from future political activity against the Vietnamese government.
The US embassy and Vietnamese government said they could not confirm whether Ly had been asked to sign any statements before leaving.
The Democratic Party of Vietnam is one of several foreign-based Vietnamese organisations with ties to political dissidents and democracy activists inside the communist country. Vietnamese authorities do not recognize the group, and several Democratic Party members who have come to Vietnam to engage in political activity have been arrested or expelled.//dpa