Mosul is 225 miles (360 kilometers) northwest of the capital, Baghdad.
In Baghdad, gunmen in a speeding car opened fire at a checkpoint run by anti-al-Qaida, pro-government Sunni militiamen in Baghdad's western suburb of Abu Ghraib, killing four and wounding three, a police officer said.
The Sunni militia, known as the Awakening Council, was formed by the U.S. forces during the height of the insurgency. They are seen as traitors by al-Qaida local branch and other militant groups.
Meanwhile, a bombing at an outdoor market in the capital's western Jihad neighborhood killed two civilians and wounded eight, the officer said.
Medical officials confirmed the casualty figures for all attacks. All officials spoke on condition of anonymity as they were not authorized to release the information publicly.
Insurgents have stepped up attacks across Iraq in the past months, sending violence to levels not seen since 2008, when sectarian killings nearly tore the country apart in the wake of the U.S.-led invasion.
Sunday's attacks brought the total number of people killed so far this month to 490, according to an Associated Press count. According to United Nations estimates, more than 8,000 people have been killed since the start of the year as insurgents seek to undermine government efforts to maintain security nationwide.
Associated Press writer Qassim Abdul-Zahra contributed to this report.
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