TIKRIT, Iraq, April 5 (Xinhua) -- Up to 35 people were killed and some 28 others wounded when IS militants attacked a neighborhood in Tikrit, the capital of Iraq's northern central province of Salahudin, a provincial security source said on Wednesday.

The attack occurred late on Tuesday night when IS militants disguised in military uniform attacked security checkpoints and stormed several houses in Zuhour neighborhood in the western part of Tikrit, some 170 km north of the Iraqi capital of Baghdad, the source told Xinhua on condition of anonymity.

The attackers broke into the houses during the night and opened fire on families randomly, the source said, adding that at least one of the attacked houses believed to be belonging to a family of a police officer.

Iraqi security forces surrounded the neighborhood to prevent them from moving to adjacent neighborhoods, while fierce clashes with the attackers broke out in Zuhour neighborhood, the source said.

The clashes resulted in the killing of at least five IS militants, three were shot dead while two others detonated their explosive vests, the source said citing latest police report.

"Most of the victims were civilians from the attacked families and the rest were security members who were killed or wounded by the clashes," the source added.

In the morning, the governor of Salahudin province imposed a curfew in the city on Wednesday, the source said.

No group has so far claimed responsibility for the attack, but the IS terrorist group, in most cases, had been behind such deadly attacks targeting security forces, civilians, and crowded markets such as cafes and mosques across Iraq.

The predominately Sunni Arab province of Salahudin has been the scene of a major offensive by Iraqi security forces and allied paramilitary Hashd Shaabi units, which managed to retake control of the province from the hands of IS militants who seized large part of it in June 2014.

The attacks came as the Iraqi security forces backed by anti-IS international coalition are carrying out a major offensive to drive out the IS militants from their major stronghold in the western side of Mosul in northern Iraq.