The United States will release 16 Saudi Arabian nationals this week from the Guantanamo Bay prison camp for suspected terrorists, Saudi Foreign Minister Saud al-Faisal said Wednesday.

An estimated 100 Saudis are being held at the U.S. military prison in Cuba, some of them for more than four years. Their detention has been an irritant in the otherwise improving relationship between the Bush administration and the Saudi kingdom, which U.S. officials say has been helpful in tracking and stopping terrorism since the attacks of Sept. 11, 2001. Most of the 19 hijackers were Saudi.

"It took us how many years to get them back?" Saud told reporters. "It hasn't been easy."

The military still holds about 480 detainees at Guantanamo following a series of releases and transfers that began in October 2002, nearly 10 months after the detention center opened.

A total of 759 inmates have been held over the years at Guantanamo, according to Defense Department documents released to The Associated Press in response to a Freedom of Information Act lawsuit.

Of those, 136 have been Saudis, making them the second largest contingent of Guantanamo prisoners, behind only the 218 Afghans.

The military has approved 136 current detainees for transfer or release, but the timing depends on when their home countries agree to accept them and whether they can assure the U.S. the men will be treated humanely, Navy Lt. Cmdr. Chito Peppler said this week.

The U.S. military has released scores of prisoners from Guantanamo to their home nations, often after repeated requests from such allies as Britain and Australia.

Saud told reporters that the 16 men are the first Saudis to be released, but another Saudi had said late last year that a handful had already been released.

The 16 will be jailed upon their return to Saudi Arabia. Some may eventually go on trial if there is evidence against them, or they could be released after a judicial review, Saud said. He would not release the men's names.