Insurgents have stepped up their threat to Iraq's oil sector. For the first time, Iraqi insurgents have sought to fire Soviet-origin Katyusha rockets toward Iraqi oil facilities. On Jan. 1, the insurgents tried and failed to fire Katyushas toward an oil refinery near the southern city of Basra. The Oil Ministry said Iraqi security forces arrested two gunners preparing to fire the rockets from a truck. A spokesman said the arrests were carried out by the ministry's protection unit. Until now, most of the attacks by insurgents comprised of sabotage or bombings of pipelines. Iraqi insurgents have hardly launched Katyusha rocket attacks or mortar against the oil sector.