Relatives of a dozen primary-school girls who died in a dormitory fire in northern Thailand are awaiting the results of DNA tests, because all but five of the bodies were too disfigured to be identified by sight.

"I can't even tell which one is my daughter, they all just look like blackened dolls," Yupin Saewa, the mother of a 10-year-old victim, said in an interview Tuesday with the state Thai News Agency.

Fifteen girls and a teacher escaped the fire Sunday night by tying bedsheets together and using them to climb down from a second-floor window at the dormitory at the Pithakkaiat Witthaya school outside Chiang Rai city. Rescuers grabbed five others from their beds.

Initial reports said 18 girls died.

The fire's cause is under investigation.