KIRKUK, Iraq, Feb. 24 (Xinhua) -- Two policemen were killed Saturday and three wounded in an attack by Islamic State (IS) militants on an oil well in Iraq's oil-rich province of Kirkuk, a police source said.

Ten to 15 IS militants carried out an attack in the evening on an oil well in Khubbaz oilfield, some 35 km southwest of the city of Kirkuk, the source from a police force tasked with protection of oil installations told Xinhua on condition of anonymity.

A fierce clash erupted between the attackers and the police force resulted in the killing of two policemen and the wounding of three others, the source said.

The attackers fled the area after reinforcement troops arrived to the scene, the source added.

During the past few months, dozens of IS militants fled their former bases in Salahudin province and Hawijah area in the west of Kirkuk after the Iraqi forces cleared these areas during major anti-IS offensives.

However, remnants of IS militants resorted to hideouts in rugged areas near the rivers of Tigris and Zab, as well as Himreen mountainous areas to continue their almost daily attacks against civilians and Iraqi forces.

On Dec. 9, 2017, Iraqi Prime Minister Haider al-Abadi officially declared full liberation of Iraq from IS militants after Iraqi forces recaptured all the areas once seized by the extremist group.

Nevertheless, small groups and individuals of IS militants are still capable of carrying out attacks against the security forces and civilians despite operations from time to time to hunt them down.