Four people have been killed and five are missing in Sicily after an explosion caused a four-storey apartment building to collapse. Two women were recovered alive from the rubble in the southern town of Ravanusa on Saturday night, and rescuers and sniffer dogs were searching for other people still missing. The local unit of Italy’s civil protection service said on its Twitter feed that the death toll stood at four. Television images showed a mass of rubble and wooden beams where the apartment block once stood, and neighbouring buildings charred and damaged. Authorities said a gas leak was the probably cause of the explosion and that an investigation had been opened. “The gas probably found a cavity in which to accumulate,” the head of firefighters in the province of Agrigento, Giuseppe Merendino, told the Rainews24 TV channel. “This pocket of gas would then have found an accidental trigger – a car, an elevator, an electrical appliance.” Soon after the explosion, the mayor of Ravanusa, Carmelo D’Angelo, appealed on Facebook for “everyone available who has shovels and bulldozers”. He said: “There has been a disaster.” He said about 50 people had been displaced from neighbouring buildings damaged in the explosion.