The Vietnamese authorities have transferred one of the country’s best known political prisoners to a notoriously harsh prison camp more than a thousand kilometres from his home in Ho Chi Minh City.
Family members said that officials had tried to persuade Tran Hyuhn Duy Thuc to leave for exile in the United States, but that he had refused.
He has been sent from a camp in Xuyen Moc near the southern metropolis to Prison Camp Number 6 in Nghe An province in north central Vietnam, making it hard for his relatives in the south, including his aging father, to visit him.
Mr Thuc, who is serving a 16 year jail term on subversion charges, has threatened to go on hunger strike on May 24 in a protest that would coincide with the visit of President Obama.
His transfer is the latest indication that the Vietnamese government is trying to force some political prisoners into exile – in the hope that the United States will ease its pressure over human rights.
Some leading democracy campaigners, including the bloggers Dieu Cay and Ta Phong Tan, were released from prison into exile in the US. Other activists are resisting, in the belief that they can best carry on the struggle for human rights and political reform by staying in Vietnam.
Mr Thuc told family members that he was willing to die for his country. He said his hunger strike was timed to coincide with the seventh anniversary of his arrest in 2009.
The internet service entrepreneur and blogger was arrested after producing a manifesto that called for a referendum on a democratic system of government.
President Obama is expected to urge respect for human rights, and the release of political prisoners, during his three day visit beginning on May 23.
White House officials said he would seek out meetings with some of Vietnam’s independent civil society activists, who face harassment, threats and occasional violence from the authorities.
An online petition for the release of Mr Thuc has received several thousand signatures.
Mr Thuc’s 16 year jail term, imposed after a brief trial in 2010, was one of the longest sentences for dissidents in recent years.
The trial was condemned by international human rights groups as a travesty of justice.