Iraqi forces retook the main government compound in Fallujah on Friday, top commanders said, a breakthrough in the nearly four-week-old operation against the Takfiri group.

Iraqi forces retook the main government compound in Fallujah on Friday, top commanders said, a breakthrough in the nearly four-week-old operation against the Takfiri group.

The elite federal forces met limited resistance from ISIL militants, who are redeploying on the western outskirts of the city, the commanders told AFP.

"The counter-terrorism service and the rapid response forces have retaken the government compound in the centre of Fallujah," the operation's overall commander, Lieutenant General Abdulwahab al-Saadi, told AFP.

Raed Shaker Jawdat, Iraq's federal police chief, confirmed the advance.

"The liberation of the government compound, which is the main landmark in the city, symbolizes the restoration of the state's authority" in Fallujah, he said.

The government lost control of Fallujah in 2014, months before IS took second city Mosul and swept across large parts of the country.

"This operation was done with little resistance from Daesh," Saadi said, using an Arabic acronym for ISIL.

"There is a mass flight of Daesh to the west that explains this lack of resistance. There are only pockets of them left and we are hunting them down."

"The top leaders are mostly gone and those left behind to defend the city are not their best fighters, which explains their performance," said a security officer speaking on condition of anonymity.