The blast wounded six other people, including four soldiers who were stationed outside the Fallujah mosque to protect worshippers, according to a senior city police official.

The unit’s commander, an army colonel, was among the dead, the official said.

A local health official confirmed the casualties. Both officials spoke on condition of anonymity because they were not authorized to release the information.

The mosque is near a government compound that houses offices for Fallujah’s mayor, city council, police and courts.

Fallujah, 65 km west of Baghdad in Anbar province, was once a capital for Iraq’s insurgency and the site of two deadly battles in 2004 with American forces. Those fights were triggered by the horrific deaths of four US contractors who were killed and mutilated in Fallujah, and their charred bodies dragged through the streets before two of them were hung from a bridge.

Today Fallujah is a gritty city near a major Iraqi highway that is beset with occasional bursts of violence.

Extremist attacks have dropped dramatically from just a few years ago, when scores of daily killing between Iraqis’ insurgents and militias brought the country to the brink of civil war. But deadly bombings and shootings still happen every day across the country.

Also Friday, hundreds of anti-government protesters rallied in Baghdad’s Tahrir Square and in Sulaimaniyah, one of the three provinces of autonomous Kurdish region in Iraq’s north, demanding better government services, an end to corruption and more jobs.

In Sulaimaniyah, 10 people were wounded, including four riot policemen, in a stone-throwing melee.