The 238-page manual gives precise instructions for guards on handling prisoners and running the camp.

The US military said the manual seemed authentic but was out of date and should not have been publicly released.

About 340 prisoners are still held at Guantanamo, which was opened in 2002 to detain people suspected of terrorism or links to al-Qaeda or the Taleban.

Allegations of abuse at the camp have been lodged by detainees, their lawyers and human rights groups.

Calls from both within the US and around the world to close the camp have gone unanswered.

Abuse prohibited

A US military spokesman said the manual was not classified but was meant for official use only.

The spokesman, Lt Col Ed Bush, said the rules "have evolved significantly" since 2003.

The document prohibits abuse or corporal punishment but says new detainees should be held in near isolation for their first two weeks.

One section of the manual says some detainees should not have access to visitors from the International Committee of the Red Cross, something the US military has denied.

Precise instructions are given on how to search a prisoner's cell, and how to pepper spray an unruly detainee.

Four pages are taken up to explain how new prisoners should be taken off the plane they arrive on and transported to the main prison camp.

A large new complex is being built at Guantanamo Bay where the US plans to hold military tribunals for about 80 of the detainees.