An oil pipeline in northern Iraq was ablaze Saturday after saboteurs blew it up in the latest attack against the insurgent-wracked country's vital oil industry. In the capital, a roadside bomb blast killed two people, officials and witnesses said. The violence came one day after the government announced the arrest of a man it described as a key figure in the country's most feared terrorist group, and a top official said the noose was tightening around its leader, Abu Musab al-Zarqawi. The pipeline, which connects oil fields in Dibis with the northern city of Kirkuk, about 35 kilometers (20 miles) to the southeast, was destroyed late Friday, an official of the state-run North Oil Co. said on condition of anonymity. He said it would take at least four days to repair the line. In Baghdad, insurgents detonated a roadside bomb in the west of the city, killing two civilians who were passing by in a vehicle at the time. Their slumped bodies could be seen in a small white car, its windshield smashed in the blast. It was not clear what the target of the attack was. U.S. Lt. Col. Clifford Kent said a U.S. tank was nearby at the time, but it was not damaged.