Prisoners held at the U.S. military detention center at Guantanamo Bay (search) have provided valuable intelligence about Al Qaeda and helped thwart terrorist attacks, the FBI said Wednesday.

Some of the prisoners have asserted that Al Qaeda leader Usama bin Laden (search) had prior knowledge of the 1998 bombings of U.S. embassies in Africa and the 2000 bombing of the USS Cole, a guided missile destroyer attacked while refueling at the port of Aden, Yemen.

Interrogation of prisoners have uncovered new details about the planning of these deadly attacks by Al Qaeda, which also is blamed for the Sept. 11, 2001, attacks in New York and Washington.

The FBI, in its weekly bulletin to 18,000 state and local law enforcement agencies, said prisoners "provided information that has led to the thwarting" of an unspecified plot against an oil tanker in the Straits of Hormuz (search), the busy entrance to the Persian Gulf.

The prisoners have described the locations of numerous terrorist training camps and safe houses around the world, and given investigators the identities of some Al Qaeda operatives, according to the FBI.

The bulletin was described to The Associated Press by a law enforcement source speaking on condition of anonymity.

In addition, the interviews have provided insight into the connections between militant Islamic uprisings in different places, from Bosnia to Chechnya to Afghanistan, the bulletin says. Common names and tactics have repeatedly come up, demonstrating to U.S. officials the breadth of Al Qaeda's reach and identifying some extremist groups allied with it.

State and local police officers are urged by the FBI to remain aware of the intelligence gained from these interviews as they investigate possible terrorist cells or support organizations in their areas.

Federal law enforcement officials also have said that captured Al Qaeda operatives, especially Khalid Shaikh Mohammed and Ramzi Binalshibh, have provided information about the group's operations and people associated with it. Those two and others are being held and interrogated at undisclosed foreign locations.

There are about 680 prisoners from 42 countries being held at Guantanamo Bay, the U.S. Navy base on Cuba's eastern tip. Most are suspected of ties to Al Qaeda and the fallen Taliban rule in Afghanistan that gave the terror organization a safe haven.

The prisoners are behind held by the military without being charged or having access to a lawyer. Some of them could be tried by U.S. military tribunals, but it is unclear when such trials might begin.

The Supreme Court in May refused to hear an appeal of a group of clergy, lawyers and professors who had demanded the prisoners be given legal representation and brought before U.S. courts to hear the charges against them.