GEORGE TOWN: An overnight fire in a school dormitory in Guyana that killed at least 19 children may have been arson, the country's police and fire services said on Monday.

The building in the central city of Mahdia was "completely engulfed in flames" by the time firefighters arrived around midnight, the Fire Service said earlier in the day.

Fourteen children died at the scene and another five in hospital. Six injured children were airlifted to the capital, Georgetown, while at least 17 others were admitted to the local hospital.

"Initial investigations suggest that it was maliciously set and our investigations are continuing," police commissioner Clifton Hicken said during a press conference.

DNA analysis is needed to identify 13 victims, he said, and will be conducted "expeditiously."

The police said in its earlier statement one student was awakened by screams and witnessed fire in the dormitory bathroom.

Most of the 19 children who died were Indigenous, Mark Ramotar, the director of the police communications department said earlier on Monday. "The dorm usually houses students from Indigenous communities," he said.

The youngest of the victims was a five-year-old boy, the son of the dormitory's caretaker.

All the other victims were girls, and according to a list from the Ministry of Education include several siblings and at least one set of twins.

President Irfaan Ali, who met with some parents of the dead after visiting Mahdia's hospital, said in a statement the country will hold three days of mourning.

Victims' families are being provided with counselling and other support, Ali's statement added.

"There are no words that can describe this magnitude of pain that our brothers and sisters are going through," he said. "This is a pain we must carry as a nation and as a family."

Prime Minister Mark Philips and Minister of Education Priya Manickchand also visited the site.

Photos published by the government showed Manickchand comforting a woman and walking into a fire-gutted single story building.