Turkish authorities have arrested three managers and charged them with negligence in the collapse of a girls' dormitory that killed 18 people last week, an official said Monday.

Mayor Mehmet Demirgul of Balcilar, the central town where the dormitory collapsed, said the headmaster, the deputy headmaster and the head of the local association that managed the dorm were charged Sunday.

An explosion, apparently caused by a gas leak, destroyed the three-story girls' dormitory in Balcilar on Friday, killing 18 people and injuring 27. All but one of the dead were female students.

The town is 300 miles south of Ankara.

It was not clear why the three managers were charged with negligence, but Ugur Ibrahim Altay, head of the local Civil Engineers Chamber, said the 18-year-old dorm was built without the proper building permits.

The negligence charge carries a penalty of up to 15 years in prison, according to Turkish penal code.

Officials said about 45 girls between the ages of 8 and 16 were staying at the dorm while attending Quran courses over the school summer break.

The Interior Ministry has also launched an investigation to see whether the Quran school was registered with authorities or illegal.