British troops patrol the perimeter of the Pul-e-Charkhi jail in Kabul, Afghanistan, where a major uprising erupted on Saturday night.
Afghan troops and police arrive on the scene and surround the jail, which contains Taleban and al-Qaeda convicts as well as ordinary criminals.
They came prepared for trouble. Gunfire has been heard from within the prison complex even as negotiations between the authorities and rioters continue.
Relatives of the prisoners - who started protesting about uniforms, then burned furniture and launched apparent escape attempts - gather outside to watch unfolding events.
Pul-e-Charkhi, a huge prison complex built in the 1970s, is notoriously run down and infamous for the disappearance of thousands of Afghans during the communist era.