A bomb went off under an oil pipeline near the northern city of Beiji on Tuesday, setting off a fire and causing huge quantities of crude oil to spill into the Tigris River, a police official said. Large plumes of black smoke could be seen rising from large oil fires still burning near the pipeline, while water in the Tigris River was contaminated with thick black oil. The United States military said the blast was the work of al-Qaida insurgents in the area. An Iraqi police official, speaking on condition of anonymity because he was not authorized to speak to the media, said the bomb went off before dawn, delaying the firefighters' arrival at the scene to extinguish the blaze. The bomb was placed under a branch of the pipeline from Beiji's al-Fatha district. The US military said in a statement that the part of the pipeline that was hit was some 2 meters (6.8 feet) underground and covered with a slab of concrete. A military spokesman said workers from Iraq's Northern Oil Company were...