Baghdad, June 29 (IANS): Iraqi security forces and allied militias on Monday regained ground near Iraq's largest oil refinery of Baiji and repelled attacks by Islamic State militants on two other oilfields in Salahudin province, security sources said.

The troops and allied militias known as Hashd Shaabi, advanced in Albu Jwari area just east of the vast oil refinery of Baiji, some 200 km north of Baghdad, a security source from the northern central province of Salahudin told Xinhua on condition of anonymity.

The troops, backed by government air power, also regained control of a strategic road adjacent to Tigris River east of the refinery and another road in Tal Abu Jrad area south of the oil refinery, the source said, without giving further details about casualties.

The troops' advance came amid continued heavy fighting in the past few days to drive IS militants out of Baiji and its oil refinery, the source added.

Separately, security forces and Hashd Shaabi militias repelled attacks by dozens of IS militants on two other oilfields, Allas and Ajil, in Himreen area in the eastern part of the province, the source added.

The battles, which started after midnight and lasted to the early morning hours, resulted in the killing of 11 IS militants and five security members and the wounding of five soldiers, the source said.

The small Ajil oilfield used to be an important source of funding for the IS, which extracted about 10,000 barrels per day and transported to other areas under its control.

The two oilfields, Allas and Ajil, were captured by IS militants following the June 10 blitzkrieg when the group seized large swathes of territories in predominantly Sunni provinces, but the oilfields were freed by the Iraqi forces in March.

Since March 2, security forces and thousands of allied Shiite and Sunni militias have been involved in Iraq's biggest offensive in order to recapture from IS militants the northern part of Salahudin province.

In Iraq's western province of Anbar, international aircraft carried out an airstrike on an IS position in Doulab area in west of the IS-held city of Heet, some 160 km west of Baghdad, leaving four IS militants killed and seven others wounded, a provincial security source told Xinhua on condition of anonymity.

The security situation in Iraq has drastically deteriorated since June 10, 2014, when bloody clashes broke out between Iraqi security forces and IS militants.