BAGHDAD, May 22 (Xinhua) -- A policeman was killed and three others wounded on Wednesday when Iraqi forces repelled an Islamic State (IS) attack on an oilfield in the central province of Salahudin.

The incident took place in the evening when IS militants waged an attack against positions of security forces tasked with protecting the Allas oilfield, some 40 km east of the provincial capital Tikrit, Mohammed al-Bazi, from Salahudin's provincial police, told Xinhua.

The troops fought fierce clashes with IS militants and prevented them from advancing on their positions, al-Bazi said, adding the clashes caused the death of a policeman and injuries of three others.

According to al-Bazi, it was not immediately clear whether IS militants sustained any causalities, as they fled the scene after reinforcements arrived.

The security situation in Iraq was dramatically improved after Iraqi security forces fully defeated the extremist IS militants across the country late in 2017.

IS remnants, however, have since melted in urban areas or resorted to deserts and rugged areas as safe havens, carrying out frequent guerilla attacks against security forces and civilians.