TIKRIT, Iraq, March 3 -- Iraqi security forces on Tuesday retook control of a small town in Iraq's northern central province of Salahudin, as part of a major offensive to free the northern parts of the province, including the provincial capital city of Tikrit, a provincial security source said.

The troops and allied Sunni and Shiite militias, covered by air support, managed in the early morning hours to free the town of Himreen in southeast of Tikrit, some 170 km north of the Iraqi capital of Baghdad, the source told Xinhua on condition of anonymity.

The IS militants fled the town after a heavy clash that left at least three of them killed, while five security members were wounded, the source said, adding that the troops also foiled two suicide bomb attacks: one by a booby-trapped tanker truck and another by a Humvee vehicle.

The liberation of Himreen is part of a major offensive launched before dawn on Monday from five directions aimed at recapturing key cities and towns seized by IS in the province.

The troops, backed by armored vehicles and Iraqi aircraft, have surrounded the town of Dour, some 25 km south of Tikrit, and regained control of many villages north of Samarra, some 120 km north of Baghdad, as well as villages in the Himreen area..

The forces are advancing cautiously as IS militants planted the roads and buildings with bombs. Only on Monday, the explosion experts defused over 150 bombs and eight car bombs.

Large parts of Salahudin province have been under IS control since June 11, a day after bloody clashes broke out between Iraqi security forces and the IS group, which took control of the country's northern city of Mosul and later seized swathes of territories in Nineveh and other predominantly Sunni provinces.