Syrian authorities arrested Labwani in 2005 following interviews in Europe with Arabic news outlets in which he called on Damascus to embrace sweeping human rights reforms.
In May 2007 Damascus authorities sentenced Labwani to 12 years in prison for "communicating with a foreign country and inciting it to initiate aggression against Syria."
The U.N. Working Group on Arbitrary Detention in March found the detention to be arbitrary, saying Labwani "had been condemned for the peaceful expression of his political views and for having carried out political activities," HRW said in a news release.
A consortium of international human rights groups, including HRW, Amnesty International and others, pointed to government interference in the Labwani trial and a history in Damascus of silencing its critics, demanding his release.
"It is now up to the U.N. member states, and especially countries like France and the U.S. that are currently engaged in a dialogue with Syria, to make the release of these dissidents a top priority," said HRW's Sarah Leah Whitson.