At least 30 people, and as many as 100, were killed in Syria's northern Raqqa province yesterday, when government warplanes bombed a gas station crowded with people, said activist groups. One activist said bombs struck a gas station in Ayn Issa town, near a border post that Syrian opposition fighters had captured two days ago. If verified, the bombing would be one of the worst casualty tolls from the Syrian military's use of aircraft in its effort to crush the armed insurgency which had grown out of opposition protests that began 18 months ago. Also yesterday, Syrian officials said that a helicopter had crashed near the capital of Damascus, close to a suburb where insurgents and government forces have battled for dominance. The official Syrian news agency said the helicopter's rotors had clipped the tail of a Syrian Arab airlines passenger jet with 200 people on board. It said the jet later landed safely at the Damascus airport and no one was injured. But an activist in Damascus said a rebel battalion shot down the helicopter, which crashed near a salt factory near the town of Douma. It was unclear whether anyone on board the helicopter was killed or injured. Further afield, there was news of a rebel victory as Syria's civil war spilled for the second time in a week across border areas. Rebel forces were reported on Wednesday to have driven government troops from a northern frontier crossing along the border with Turkey in a bid to expand supply and infiltration routes. Turkish schools in the region were closed on Wednesday after intense overnight clashes, reported the semi-official Anatolian News Agency.