Detainees at an Iraqi detention facility tried to overpower their guards during a prison break Sunday morning in a violent clash that left 16 people dead, including six police officers, officials said.

The melee at the Ministry of Interior's Baghdad compound raises questions about how a group of detainees at what is supposed to be one of the most secure facilities in the country managed to launch such a fierce attack.

The detainees, some of whom are accused of belonging to al-Qaida in Iraq, were being moved between buildings at the sprawling ministry compound in eastern Baghdad when some of the detainees tried to overpower the police and take away their weapons, said a ministry official on the scene. Initial reports suggest the detainees were not shackled or restrained.

He said about 20 to 25 prisoners were being moved when the clash broke out. They managed to seize weapons from some of the guards and open fire.

In the ensuing melee, which lasted for three to four hours, six police and 10 detainees were killed. An additional eight police officers and six detainees were wounded.

Among the detainees were accused al-Qaida in Iraq members involved in the attack last October on a Baghdad church that left 68 people dead, security officials said. Brigadier Muaeid Mohammed Saleh, the head of a department responsible for combating terrorism and organized crime in eastern Baghdad, was also killed in the violence, the ministry official said.

The injured detainees were brought to Baghdad's al-Kindi hospital under tight security, treated and then taken away again by security officials to an unidentified location, officials said.

Police and hospital officials confirmed the casualties.

All the officials spoke on condition of anonymity because they were not authorized to speak to the media.

It is the latest embarrassing incident for Iraq related to its detention facilities.

In January, 12 inmates, many believed to have links to al-Qaida in Iraq, were awaiting trial in a temporary detention center in the southern city of Basra when they obtained uniforms and walked out in disguise. They scattered after that to avoid a massive manhunt. At least two were later picked up by security officials in northern Iraq.