At least 35 people were killed by airstrikes early Sunday morning in northwestern Yemen, where rebels have been fighting a guerrilla war against Yemeni and Saudi forces, witnesses said. The airstrikes, in the remote town of Razah not far from the Saudi border, appeared to be the deadliest attack in months in the intermittent war in Saada province. One witness said the bombs had struck a market, killing at least 35 people who appeared to be civilians. Hours later, the rebels posted an Internet statement saying 70 civilians had been killed and 100 wounded, after fighter jets struck the town more than 50 times. The town is 'tens of kilometers' from the war zone where rebels have been fighting the Saudi military, the rebel statement said. The rebels, known as Huthis after the clan of their leader, said the airstrikes were carried out by Saudi war planes. Saudi military officials could not be reached unday night, and Yemeni officials declined to comment. The Huthis have fought an intermittent war with the Yemeni government for more than five years. The conflict intensified in August, when the Yemeni president, Ali Abdullah Saleh, declared that he meant to finish off the rebellion once and for all. The Saudis became involved early last month, when Huthi fighters seized a strategic hilltop on the Saudi border and killed a Saudi border guard. The rebels said the Saudis had forced their hand by allowing the Yemeni military to use the hill to attack them. The Saudis, with a vastly superior military force, pushed the rebels from the border using airstrikes and mortar fire. But the Huthis continued their attacks, and succeeded in capturing a number of Saudi soldiers. If the airstrikes in Razah were in fact carried out by Saudi forces, the attack could amplify anger against the Saudis among Yemeni tribes. That could intensify the challenges the Saudis face in a volatile area that is flooded with weapons, where Yemen's own efforts to assert control through military force have often backfired. The Saudi role has already threatened to extend a conflict with troubling sectarian overtones. The Huthis belong to the Zaydi sect, an offshoot of Shiite Islam. They have long complained that the Yemeni government, with encouragement from the Saudis, fostered hard-line Sunni militants in the Zaydi heartland of Saada province. The Yemeni government has long accused Iran of supporting the Huthis, despite the fact that Zaydism is doctrinally distinct from the Shiism practiced in Iran. Iran has denied aiding the rebels, but Iranian state news media have reported on the Huthis sympathetically. 