Baghdad, April 18 (IANS): Iraqi security forces on Saturday retook control of an oil refinery in Salahudin province after heavy clashes with the Islamic State (IS) militants, a provincial official said.

"The troops backed by allied Shia and Sunni militias have completely liberated the vast oil refinery of Baiji after they drove out the IS militants," Jasim Jbara, head of the security committee of Salahudin provincial council, told Xinhua news agency over telephone.

The security forces also started a clearing operation across the refinery to defuse landmines and roadside bombs planted by the IS before withdrawing from their positions in the refinery, Jbara said.

Meanwhile, the security forces managed to free the eastern and central parts of the nearby town of Baiji, some 200 km north of capital Baghdad, after pushing back the IS militants who are still fighting in western neighbourhoods of the town, Jbara added.

The battles for the oil refinery and the nearby Baiji were part of a large-scale operation launched on Wednesday aimed at recapturing areas seized by IS militants in Salahudin, particularly after the militants progressed inside the huge oil facility on Tuesday.

The battles came more than two weeks after Iraqi security forces regained control of the provincial capital city of Tikrit, some 170 km north of Baghdad.

Since March 2, some 30,000 Iraqi troops and thousands of allied Shia and Sunni militias have been involved in Iraq's biggest offensive to recapture the northern part of Salahudin province, including Tikrit and other key towns and villages, from IS militants.

Large parts of the province have been under IS control since June 2014, after bloody clashes broke out between Iraqi security forces and the group.