Updated

Dozens of Guantanamo inmates are protesting their imprisonment with a sit-in and signs to mark the ninth anniversary of the prison camp's opening.

The Center for Constitutional Rights says the prisoners are refusing to return to their cells for the required nightly lockdown and that they are sleeping in the recreational yard and other areas.

The defendants' attorneys say their clients at the prison on the U.S. Navy base in Guantanamo Bay, Cuba have not received due process.

The center said in a statement Thursday that the peaceful protest at Camps 5 and 6 began nearly two weeks ago. A spokeswoman did not return calls seeking comment.

Guantanamo once held nearly 800 detainees, mostly suspected terrorists. About 170 remain.