A fire in a school dormitory in Guyana that killed 19 children was lit by a student after her mobile phone was confiscated, police said on Tuesday.

"A female student is suspected of having set the devastating fire because her cellular phone was taken away by the dorm's mother and a teacher," according to the official report.

Police said that there were 57 pupils in the dormitory that went ablaze.

A government pathologist found that the cause of death of six individuals was smoke inhalation and burns.

Thirteen sets of remains had been moved to Guyanese capital Georgetown for DNA identification.

Nearly 30 other children were hospitalized after the fire.

On Monday, President Irfaan Ali declared three days of national mourning. The Guyanese head of state met with parents of the deceased after visiting Mahdia's hospital.

What we know about the suspected arson attack

The fire broke out in a school dormitory in the town of Mahdia in central Guyana.

An unnamed government official told the Agence France-Presse (AFP) news agency that that the student was under police guard at the district hospital in Mahdia. The official said that the girl had admitted to the arson, with police seeking advice on whether to charge her.

"They (staff) took away the phone from the girl and the girl threatened the same night that she will burn down the building and everybody heard her," an anonymous official told AFP.

Minister of Education Priya Manickchand told Reuters that allegations that the dormitory did not have modern fire alarm systems was "under investigation."

"What must come of this is improvement across the sector," she said.