ISIS is still in control of Fallujah along with large swaths of territory in Syria.

TIKRIT Iraq (Reuters) – Sunni insurgents overran parts of the city of Samarra in northern Iraq early on Thursday, bringing them within striking distance of a Shi’ite shrine that was previously the trigger for sectarian war.

The offensive is part of an escalating war between Iraq’s Shi’ite-led government and militants who have been regaining ground and momentum over the past year, particularly in the west of the country bordering Syria.

The Sunni militants blew up a police station around 25 km south of Samarra overnight, security sources said, killing several policemen before advancing on the city in pick-up trucks, raiding checkpoints on the way.

After entering the city from both east and west, they seized control of the municipality building and university, raising the black flag of the Sunni militant ‘Islamic State in Iraq and the Levant’ (ISIL) over both buildings, police said.

They also occupied Samarra’s two largest mosques and announced the “liberation” of the city via loudspeaker, urging residents to join their jihad (holy war) against the government.

Officials said the militants had reached within about two kilometers of the Askari shrine, whose destruction by insurgents in 2006 touched off the worst bout of Sunni-Shi’ite bloodletting to follow the U.S.-led invasion of 2003.