BAGHDAD, Sept. 9 (Xinhua) -- A bomb explosion has struck an oil pipeline in Kirkuk oilfield in northern Iraq, setting huge fire, while four security members were wounded by another bomb near the site of the first blast, a local security source said Sunday.

The sabotage of the oil pipeline took place around Saturday noon, when a bomb planted in the pipeline used to convey crude oil from Bai Hassan oil field to an oil pumping facility in Debis area in the northwest of Kirkuk City, some 250 km north of Baghdad, Salih al-Obeidi from the Kirkuk police told Xinhua.

Fire engines and civil defense teams rushed to the scene in an attempt to put out the flame, the source said.

Meanwhile, another roadside bomb planted on a road leading to the site of the first blast detonated near a police vehicle heading to the fire to secure the area, leaving four policemen wounded, Obeidi said.

Iraq's oil pipelines have been frequently attacked by insurgents, including the Islamic State (IS) militants, since the U.S.-led invasion in 2003.

In December 2017, Iraq officially declared full liberation of Iraq from IS militants after Iraqi forces recaptured all the areas once seized by the extremist group.

However, militant remnants regrouped in urban and rural areas or fled to desert and rugged areas, carrying out attacks against security forces and civilians despite operations from time to time to hunt them down.