Sunni militants captured the northern Iraqi town of Tal Afar early on Monday, its mayor and residents said, the latest blow to the nation’s Shiite-led government a week after it lost a vast swath of territory in the country’s north.

The town, with a population of some 200,000 people, mostly ethnic Shiite and Sunni Turkomen, was taken just before dawn, Mayor Abdulal Abdoul told The Associated Press.

The ethnic mix of Tal Afar, 420 km northwest of Baghdad, raises the grim spectre of large-scale atrocities by Sunni militants of the al-Qaida-inspired Islamic State of Iraq and the Levant, or ISIL, who already claim to have killed hundreds of Shiites in areas they captured last week.

A Tal Afar resident reached by phone confirmed the town’s fall and said militants in pickup trucks mounted with machineguns and flying black jihadi banners were roaming the streets as gunfire rang out.

The local security force left the town before dawn, said Hadeer al—Abadi, who spoke to the AP as he prepared to head out of town with his family. Local tribesmen who continued to fight later surrendered to the militants, he said.

“Residents are gripped by fear and most of them have already left the town to areas held by Kurdish security forces,” said al-Abadi.

The fall of Tal Afar comes a week after Sunni militants captured Iraq’s second—largest city, Mosul, and Saddam Hussein’s hometown of Tikrit in a lightening offensive.

Fighting in Tal Afar began on Sunday, with Iraqi government officials saying that ISIL fighters were firing rockets seized from military arms depots they captured in the Mosul area. They said the local garrison suffered heavy casualties and the main hospital was unable to cope with the wounded, without providing exact numbers.

Over the weekend, militants posted graphic photos that appeared to show their gunmen massacring scores of captured Iraqi soldiers. The pictures, on a militant website, appear to show masked ISIL fighters loading the captives onto flatbed trucks before forcing them to lie face—down in a shallow ditch with their arms tied behind their backs. The final images show the bodies of the captives soaked in blood after being shot at several locations.

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