An official said policemen had captured one of those who escaped [AFP]

Nineteen detainees, including two men sentenced to death and several alleged al-Qaeda leaders, have escaped from a temporary prison in northern Iraq.

The group reportedly drugged guards and fellow inmates using narcotic-laced dates that put them to sleep before breaking out of al-Tasfirat prison in the city of Kirkuk on Friday.

"They removed the ventilator in the bathroom and used blankets to jump from the opening," Major-General Torhan Abdulrahman Youssef, a deputy police chief, told Reuters news agency.

"Most of them are accused in accordance with article 4 [terrorism]. Investigations are ongoing."

The group was made up of men allegedly belonging to al-Qaeda and Ansar al-Sunna, a Salafist group that has claimed several attacks against US and Iraqi security forces, a security official said.

Police said on Saturday that prison officials and guards had been detained over the incident. The entire staff was being questioned.

One of the escaped inmates had been captured, an official said.

The detention facility is housed inside a fortified police compound in central Kirkuk. Suspects are usually held there while waiting to be tried in court.

"We consider today's incident to be very clear negligence by the security forces," said Abdullah al-Asi, a Kirkuk provincial councillor, alleging the prison break was an inside job.

Last September, 35 prisoners facing terrorism charges escaped via a sewage pipe from a temporary jail in the northern
city of Mosul, an al-Qaeda stronghold which has seen a number of big prison breaks. Iraqi police were able to recapture 21 escapees.