Three Pakistani children and a man were killed on Thursday when explosives stored in a house detonated in a town on the Afghan border, officials said. The explosion also damaged two houses in Killi Mohammad Rasul village just outside the town of Chaman which faces the Afghan border town of Spin Boldak. \"Three children and a man were killed in an explosion at a house,\" senior administration official Abdul Fateh Bhanghar told AFP. Ten others, including six children, were also injured when the roof collapsed under the force of the explosion. Health officials said three children were evacuated with serious injuries to Quetta, the capital of the restive southwestern province of Baluchistan. \"The dead included a 22-year-old man, a 14-year-old boy and two girls aged five and four,\" said Akhter Muhammad, the head of local hospital in Chaman. \"They had stored mines, bullets and explosives in the house,\" local government official Abdul Khaliq Mandokhel told AFP. Violence has surged in Baluchistan, which borders Afghanistan and Iran. The province is rife with Islamist militancy and sectarian violence.