At least 19 teeange girls died after a shelter home in Guatemala caught fire during a fight between the inmates and the staff accused of sexual abuse and other maltreatment.
The victims were between the age of 14 and 17.
Another 25 people suffered burns, according to the firefighting service. The injured were taken to hospitals in Guatemala city.
The fire engulfed the facility when some of the inmates set ablaze a mattress, said Abner Paredes, a prosecutor defending children's rights.
The fire broke out in the adolescent female wing of the state-run Virgin of the Assumption Safe Home.
The facility, built in 2006, is located in San Jose Pinula, a village 10 kilometers (six miles) east of the capital Guatemala City.
A former employee of the facility, Angel Cardenas, said the packed centre was a ticking time bomb and the tragedy was something that "was to be expected".
The facility was designed to have 400 inmates but was home to nearly double that number.
At the entrance of the facility, whose imposing, barbed wire-topped concrete wall showed no sign of the drama inside, crying relatives crowded the entrance in search of news of the children kept there. Police blocked access to them and to journalists.
A few survivors were seen hugging kin on the pine tree-lined road. But many other family members were left with no news.
"They don't want to give any information at all," stormed Rosa Aguirre, a 22-year-old street vendor who had rushed from the capital to see if her two sisters, aged 13 and 15, and her 17-year-old brother were among the casualties.
She said many frustrated people had gone to the hospitals to see if their relatives were there.
Aguirre said she, too, had lodged complaints about how the center's charges were treated, but received no attention.
She said brawls broke out often, and her brother was sometimes put in a dark isolation cell nicknamed the "chicken coop." She said she had tried in vain to be given custody of her siblings after their mother's death four months ago.
Guatemalan media said the shelters' occupants had revolted overnight and into Wednesday against alleged sexual abuse by staff, and over poor food and conditions.
The United Nations children's fund UNICEF called the fire and the deaths a "tragedy." It added in a Twitter post that "these children and adolescents must be protected."
The center, supervised by state authorities, hosts minors under age 18 who are victims of domestic violence or found living on the street.
They are sent there by court order and are under the responsibility of the social welfare ministry.
The shelter has been the target of multiple complaints alleging abuse. Dozens of children have run away in the past year, reportedly to escape ill treatment inside.