A three-story girl's dormitory collapsed in central Turkey early Friday, killing 13 students, officials said. An estimated six other students were still under the rubble. Authorities believe the building in the village of Balcilar collapsed after a large gas canister exploded, the village's mayor, Mehmet Demirgul, said. At least 20 students were brought out of the debris with injuries, said Galip Sef, an official with the local emergency services. Three of the students sustained severe burns, he said. An estimated 40 girls, between the ages of eight and 16, were staying at the dormitory in Balcilar, near the town of Taskent, in the Toros mountain range. The students were attending Quran courses during the school summer break.