More teenagers have died from serious burns after a fire at an overcrowded children's shelter near the capital of Guatemala, raising the death toll to at least 34.

Nineteen victims were found dead at the scene, and 15 more succumbed one by one to their grisly injuries at hospitals in Guatemala City.

Several more girls were in serious condition on Thursday, some with severe burns over more than half their bodies.

The fire at the government-run Virgin of the Assumption Safe Home in San Jose Pinula, 10km east of Guatemala City, focused attention on allegations of sexual and other abuse in the facility.

President Jimmy Morales said on national television that he had ordered the dismissal of the shelter's director.

The blaze was believed to have started during an overnight rebellion in the centre, which holds nearly double the 400 people it was designed to house, against alleged sexual abuse by staff and over poor food and living conditions.

On Wednesday morning someone set fire to mattresses in the girls' section of the rural campus, authorities said. The blaze quickly spread through two dorms.

Some young people tried to escape, according to local media reports.

Morales said that before the fire, orders had been given to transfer some of the youths to other facilities because of the overcrowding.

"They were serving food to the teenagers when some of them started a fire in a mattress and that's how the fire was set," said Abner Paredes, a prosecutor defending children's rights.

A 'time bomb'

Guatemala has begun a three-day mourning period.

Human rights activists held a vigil on Wednesday night, lighting candles and placing flowers outside the shelter and in the main square in Guatemala City.

"It was a ticking time bomb. This was to be expected," one of the centre's former employees, Angel Cardenas, said at the vigil, adding that he had lodged several warnings about conditions inside.

"There has been a small protest in front of the presidential palace in Guatemala City where people were taking burned dolls and laying them out at the steps of the building," Al Jazeera's David Mercer, reporting from outside the shelter, said on Thursday.

"There is a lot of public indignation, suffering and confusion that is continuing in Guatemala," he said, adding that relatives of children at the centre continued arriving at the scene for a second consecutive day on Thursday.

On Wednesday, anxious family members had gathered outside the home, while others rushed to hospitals to see if their relatives were there.

"They don't want to give any information at all," said Rosa Aguirre, who rushed from the capital to see if her two sisters, aged 13 and 15, and her 17-year-old brother were among the casualties.

Aguirre said she had lodged complaints about how the centre's residents were treated, but received no attention.

Brawls broke out inside often, and her brother was sometimes put in a dark isolation cell nicknamed the "chicken coop", she said, adding that she had tried in vain to gain custody of her siblings after their mother's death four months ago.

The centre hosts children under the age of 18 who are victims of domestic violence or found living on the street.

Sent by court order, the residents are under the responsibility of the social welfare ministry.

The shelter has been the target of multiple complaints alleging abuse. Dozens of children run away in the past year, reportedly to escape ill treatment.

Calls to close shelter

A prosecutor for upholding children's rights, Hilda Morales, told reporters she was requesting the shelter be closed.

"We are going to ask for the immediate closure of the centre, and attribute administrative and criminal responsibility against those in charge of the centre for not fulfilling their duty," she said.

She noted that last year the Inter-American Commission on Human Rights had found in favour of several adolescents who had alleged mistreatment and sexual abuse in the shelter.

Another prosecutor tasked with protecting children in the country, Harold Flores, told the radio station Emisoras Unidas that since last year, complaints had surged from minors who fled the shelter alleging sexual abuse.