BAGHDAD - A prison riot in Iraq's northern city of Tikrit led to more than 200 detainees freed and at least five policemen killed on Thursday night, local security officials said.

Dozens of detainees seized weapons from guards when supper was distributed, a local police source told Xinhua on condition of anonymity because he is not authorised to speak to the media. The escaped detainees subsequently opened the cell doors and took control of the prison.

The prison housed some 900 prisoners including scores of al-Qaida members. The source said more than 200 have escaped and 33 of them were recaptured by the security forces later.

At least five policemen were killed in the riot and two others were wounded including the prison director, Brigadier Leith Alskmana, the source said. He dismissed earlier reports that militants stormed the prison from outside.

Large reinforcement of military and police personnel from Samarra and Baghdad have arrived at the scene and were hunting down the detainees on the run. Helicopters were seen patrolling and a curfew was imposed in the whole city. The security forces managed to regain control over the prison, but exchange of fire can be still heard at the scene, the source added.

Another security official who asked not to be named told Xinhua that the escaped prisoners shot randomly at local residents during their flight, killing a number of civilians and security members, but he did not specify the death toll.

The official feared dozens of policemen who stood guards were killed inside the prison once the detainees seized control.

He believed it was al-Qaida linked prisoners who led this assault. Al-Qaeda's front group the Islamic State of Iraq said in July that it was launching a new military campaign aimed at recovering territory and helping its jailed members escape.

Tikrit, 170 km north of the capital Baghdad, is the hometown of former leader Saddam Hussein and a stronghold of Sunni insurgents. Prison breaks happened from time to time in the restive city in recent years.