FACTBOX: Facts about the Guantanamo prison camp

(Reuters) - A trial began this week at the controversial war crimes court at the U.S. naval base at Guantanamo Bay, Cuba, for Yemeni captive Ali Hamza al Bahlul, who is accused of acting as Osama bin Laden's media director. Here are some facts about the Guantanamo detention operation.

- The United States holds about 255 prisoners at Guantanamo and has released or transferred to other governments about 500 other suspects previously held there.

- Four Guantanamo prisoners committed suicide by hanging; three in June 2006 and one in May 2007. A fifth prisoner died of colorectal cancer in December 2007 and is the only one to die of natural causes.

- The detention camp was set up to hold foreign terrorism suspects captured after U.S.-led forces invaded Afghanistan to root out al Qaeda and its Taliban protectors in response to the hijacked plane attacks of September 11, 2001, that killed nearly 3,000 people in New York, Washington and Pennsylvania.

- The first captives arrived on January 11, 2002.

- The Pentagon plans to try as many as 80 prisoners but only two have been tried so far. Osama bin Laden's driver, Yemeni captive Salim Hamdan, was convicted in August 2008 of providing material support for terrorism and sentenced to 5 and 1/2 years in prison. Australian David Hicks admitted training with al Qaeda in Afghanistan and pleaded guilty to providing material support for terrorism. He was sent to Australia to finish a nine-month sentence that ended on December 29, 2007.

- Prosecutors are seeking the death penalty in six pending cases, including those of five men accused of plotting the September 11 attacks and one accused of masterminding the bombing that killed 17 U.S. sailors aboard the warship USS Cole in Yemen in 2000.

(Reporting by Jane Sutton; Editing by David Storey)