A three-story girls dormitory collapsed in central Turkey on Friday, killing at least 17 students and setting off a search for a half dozen people believed to be under the rubble, authorities said.

Frantic rescue workers removed debris with shovels, pickaxes and their bare hands in search of any survivors. The girls, between ages of 8 and 16, were attending Quran courses during the school summer break.

"We are hearing voices. I believe those inside the rubble will be saved," Balcilar Mayor Melmut Demirgul told reporters hours after the collapse.

But hopes of finding any more survivors began to fade later Friday. Rescue teams pulled out the body of one girl in the afternoon, raising the death toll to 17, Anatolia reported.

Demirgul initially told reporters a large gas canister explosion was believed to have caused the collapse. However, the state-run Anatolia news agency and other reports later said the explosion was most likely caused by a leak from a gas installation there.

Interior Minister Besir Atalay, who traveled to the area, said at least 16 were killed. He said an estimated five or six students were waiting to be rescued.

Besides the fatalities, at least 27 students were brought out of the debris with injuries, said Hasan Kucukkendirci, who heads the local health authority. Galip Sef, an official with the local emergency services, said three of the students sustained severe burns.

Provincial Gov. Osman Aydin said an estimated 40 to 45 girls were staying at the dormitory.

Anatolia news agency quoted one student, Merve Avci, as saying she had got up to wash before pre-dawn prayers when she and some teachers heard a strange sound and went to the kitchen to investigate.

There, they saw a loose gas pipe and she returned to her room after the teachers told her to close the door.

Soon after, Avci told Anatolia, she smelled gas and there was an explosion. Half of the building collapsed, but she was in the section that remained intact. She said flames rose from the basement toward the top of the building.

Television footage showed residents, some using their bare hands, trying to remove the rubble from a flattened, concrete building.

One girl in pajamas could be seen being carried to a hospital. Another could be seen being treated on the back seat of a van, before being moved onto a stretcher and taken away, groaning in pain.

At least four military helicopters ferried special military rescue teams to the scene. Rescuers, aided by dogs, were trying to locate survivors, Kucukkendirci said. Anatolia said helicopters flew the injured to a hospital in Konya city.

In 2004, an 11-story apartment building collapsed in Konya, killing 92 residents. The collapse was blamed on faulty refurbishment work. A year earlier, a school dormitory in Bingol, southeast Turkey, collapsed in an earthquake, killing 83 children.