A federal police headquarters in northern Iraq was hijacked by scores of gunmen, killing many people as a tanker loaded with explosives was crashed into the building on Friday, a government official said.
Since victims remained trapped beneath the building in the village of Injana, the total number of casualties was still impossible to ascertain, Reuters reported.
However, the battalion commander and his assistant were among the dead.
The gunmen, who are responsible for taking over another town in the area called Serha as well, were still fighting and resisting security forced, the mayor of the nearby town of Sulaiman Pek, 160 km (100 miles) north of Baghdad, said.
Last month, the Sunni Islamic State's black flag was raised in Iraq as Sulaiman Pek was occupied by militants last month.
Brigadier General Raghib Ali, who was responsible in driving the militants out of Sulaiman Pek, was allegedly the main target of the tanker bombing, security officials said.
"In Ramadi, six people were killed when a suicide bomber blew himself up inside a mosque where a funeral was being held for an officer who died in a roadside bombing earlier this week, medical and security sources," Reuters reported.
"Meanwhile in Falluja, about 300 militants paraded through the main streets of Falluja late on Thursday, dressed in black and bearing ISIL's banner. They showed off military Humvees, armored vehicles and some weapons they said they had taken from soldiers during the fighting."
The insurgency, which is as an extension of the civil war in Syria, is in need of support and help from the international community, Shi'ite Prime Minister Nouri al-Maliki said. He has also declared war on Sunni militants.
The country's once-dominant Sunni minority has been marginalized by Maliki's policies, critics said. It has even created the conditions for militants to thrive, Reuters reported.