TIKRIT, Iraq - At least 17 people were killed in attacks across Iraq on Sunday as troops fought to evict Islamist militants from the northern town of Sulaiman Pek, security sources and medics said.

Armored vehicles and special police forces with heavy machine guns arrived in Sulaiman Pek to reinforce troops battling there for several days backed by helicopters gunships.

"Clashes are continuing today in the town center," the town's mayor, Talib Mohammed, told Reuters. "The situation is still unclear. We can't even look out of the window, as bullets and blasts are not stopping."

Militants raised the black flag of the Islamic State in Iraq and the Levant (ISIL) - a hardline Sunni group also fighting in neighboring Syria - over parts of Sulaiman Pek, 160 km (100 miles) north of Baghdad, on Thursday.

Sunni militancy has been on the rise over the past year, especially in the western province of Anbar, where the army is besieging the city of Falluja, overrun by insurgents on Jan. 1.

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