A veteran Vietnamese activist has been arrested after calling for a Middle East-style uprising in the country.
Nguyen Dan Que, 69, was later released but faces further questioning after an alleged internet appeal for the overthrow of the communist government.
Mr Que was detained in Ho Chi Minh City on Saturday. The democracy advocate has spent a total of 20 years in jail.
Following the fall of the presidents of Egypt and Tunisia, unrest has been spreading throughout the Middle East.
Analysts say the popular uprisings have also unnerved authoritarian governments further afield.
Mr Que urged young Vietnamese to follow the lead of the Arab world, reports said.
During a raid on his home, police allegedly seized thousands of anti-government documents, including an "appeal to all people" which called on the public to rise up against the government, the Tuoi Tre newspaper said.
The family of Mr Que confirmed he had been released but told the BBC he had been asked to attend daily "interrogation sessions".
Mr Que has been in and out of jail since 1978, after calling for a multi-party political system.
He was last detained in 2003, after writing a series of internet articles criticising government curbs on journalists.
He was sentenced to 30 months in jail for "abusing democratic rights to infringe upon the interests of the state", and was released in 2005 under an amnesty.
In 1990 he was sentenced to 20 years in prison for his involvement in a political reform movement - but was granted amnesty in 1998 on the understanding he would resettle in the US - but he stayed in Vietnam.