MOSUL, Iraq, Feb. 17 (Xinhua) -- An intelligence officer and three gunmen were killed Sunday in Mosul, the capital city of Iraq 's northern province Nineveh, a provincial police source said.
The incident took place in the morning when three gunmen shot dead Captain Mohammed Rakan, an officer in the provincial intelligence department, in front of his house, the source told Xinhua on condition of anonymity.
An Iraqi army patrol close to the scene chased the attackers and killed them after a fierce clash, the source said.
The incident came one day after the killing of a senior officer and two policemen when two suicide bombers, wearing explosive vests, tried to attack the house of the commander of the rapid reaction police force in the town of Tal Afar, some 70 km west of Mosul.
Guards of the commander's house opened fire on the two attackers, shooting dead one of them and blowing up the vest of the other.
Nineveh province has long been a stronghold for insurgent groups, including al-Qaida militants. Its capital city Mosul, some 400 km north of the Iraqi capital city of Baghdad, is one of the country's most restive cities.