Four prisoners at the Karkh prison in Baghdad have fled in an escape which authorities have described as "regrettable."

US military officials running a section of the jail, which was formerly Camp Cropper, said the men who escaped were regarded as dangerous, as they had ties to al-Qaeda.

The inmates were found to have escaped from the US section after a meal call.

While Karkh prison was turned over to Iraqi authorities in July, US forces retain custody of about 200 of the most dangerous prisoners, including those with ties to terrorists or Saddam Hussein’s former regime.

Karkh prison, which houses around 1,500 detainees, was the last US prison in Iraq.

It became infamous after a period in which prisoners were found to have been abused by American jailers.