U.S. military officials say a Yemeni detainee at Guantanamo Bay has died of an "apparent suicide."

The Joint Task Force that runs the U.S. prison in Cuba said guards found 31-year-old Muhammad Ahmad Abdallah Salih unresponsive and not breathing in his cell Monday night.

In a Tuesday statement, the military says the detainee was pronounced dead by a doctor after "extensive lifesaving measures had been exhausted."

The Yemeni prisoner, known as Al-Hanashi has been held without charge at Guantanamo since February 2002. Military records show he was about 31. His is the fourth apparent suicide at Guantanamo.

The U.S. military says the remains will be autopsied by a pathologist from the Armed Forces Institute of Pathology.