At least 38 people were killed and 37 wounded in a series of bombings and attacks that rocked government-held areas in Syria's Sweida province on Wednesday, state media and opposition activists reported.The Islamic State (IS) terror organisation is believed to be behind the violence.The Syrian Observatory for Human Rights (SOHR) said IS suicide bombers detonated bomb vests and explosive devices in Sweida city in tandem with an attack by the group on towns in the eastern countryside of Sweida, the BBC reported.Three suicide bombers set off their bomb vests near a grocery market as well as the roundabouts of Mashnaqa and Najmeh in the city, adding that explosive devices were detonated in the same areas.State news agency SANA said one bomber detonated himself in the market area, adding that two others were killed as they were hunted down by the authorities.Reports also said government forces were "targeting positions of the IS in countryside to the east of Suweida".The Syrian military, backed by Russian forces, recently launched an operation to drive the rebels from their remaining strongholds in the south-west.At least 270,000 people fled their homes in the region as fighting continues, the UN said.On Sunday, Israel allowed the evacuation of hundreds of White Helmets civil defence workers who were trapped in a war zone in southern Syria.The Syrian government condemned the move, describing it as a "criminal operation" by Israel and others.