London (PTI): Noted Human rights activist Dr. Binayak Sen, who was released on bail from a Chhattisgarh jail in May, said his liberty is still under threat as a campaign was launched in his support at the ongoing Edinburgh Festival.

Highlighting his case at the festival, human rights group Amnesty International has urged people to join a photo petition by posing with a placard calling for charges against him to be dropped.

In an interview, Dr. Sen told the local media: "The Chhattisgarh government seems determined to continue the trial and the harassment, so we do not see an end in sight."

He added: "Healthcare facilities for poor people in rural areas are unavailable and inaccessible. Our endeavour was to set up primary heathcare for some of most the deprived communities. This opened up questions of entitlement and access."

Dr. Sen was accused of acting as a "courier" for Narayan Sanyal, an imprisoned Maoist leader.

Describing his arrest, Dr Sen said it was not a great shock. "It was distressing, but not entirely unexpected.

"I had no special privileges, but I was also not subjected to special maltreatment, except (for) three weeks during which I was in solitary confinement. The authorities took special measures to keep me isolated."

John Watson, Amnesty International Scotland director, said: "This is the perfect time to remind people about the importance of free speech."