Saboteurs set fire overnight to a pipeline that carries crude oil from the oilfields of Kirkuk to Baghdad's Dora refinery, said police on Saturday. The police said assailants blew up the part of the pipeline that passes through the northern city of Samarra by placing an improvised explosive device under it. Samarra is 110 kilometres north of Baghdad. Firefighters rushed to the scene to put out the fire. Saboteurs have repeatedly targeted Iraq's oil pipeline network. According to Oil Ministry statistics, 246 attacks were carried out on oil industry infrastructure in 2004. Meanwhile in the northern city of Mosul, gunmen shot dead three policemen while they were on patrol Saturday, said the police.