Iraqi officials say Islamic State (IS) fighters have raised their black flag over the main government building in Ramadi, the capital of the western Anbar Province.
The militants used six suicide car bombs in their May 15 assault on Ramadi's center, where the compound that houses the main police headquarters and governor's office is located.
Ramadi's Mayor Dalaf al-Kubaisi said the militants seized other parts of the city and that at least 10 police officers were killed in the fighting.
There are also reports of summary executions.
IS fighters captured large swaths of territory in June 2014 during a lightning advance through western and northern Iraq.
They have been battling against government forces for months to take control of the entire Anbar Province.
Up till now, Ramadi, located some 110 kilometers from Baghdad, had been mostly under government control, with IS militants holding some of the outskirts.