The United States has said three more inmates at the prison for suspected al-Qaeda members and others at Guantanamo Bay, Cuba, have attempted suicide.
This brings the number of attempted suicides to 10 this year and has prompted criticism from human rights groups at US treatment of its prisoners.
Nineteen inmates have tried to kill themselves, most by hanging, since the detentions at the US naval base at Guantanamo Bay began in January 2002, said a US Navy spokeswoman. None have died.
"They actually have a mental-health team, which is psychologists and psychiatrists and medical doctors working together," the spokeswoman said. She said the men "are getting treated humanely under the principles of the Geneva Convention".
But Michael Ratner, president of the New York-based Centre for Constitutional Rights activist group, said suicide attempts at Guantanamo was a "very serious" issue.
"Suicide attempts could be the result of very heavy interrogation techniques, people being very frightened about what's going to happen to them, and this is a way of getting an escape from severe interrogations that might include torture," Mr Ratner said.
He said the men were in legal limbo, with no charges, no contact with family or lawyers "and a detention that may go on forever, according to our own government".