A fire ripped through the dormitory of a boarding school in central Kenya, killing 18 boys who were sleeping and injuring 27 others, police and government officials said.

The death toll could rise, police warned on Friday, following the disaster at Hillside Endarasha Primary School in Nyeri county, as the survivors are being treated in numerous hospitals.

Government spokesman Isaac Mwaura said the boys were in grades 4 to 8, putting their ages at about nine to 13 years. The dormitory housed 156 boys.

Police said the average age of the victims was around nine.

Vice President Rigathi Gachagua said 70 pupils remained unaccounted for, although he added that some may have been taken home by their parents in the night.

The cause of the fire on Thursday night was being investigated, police spokeswoman Resila Onyango said, adding that “necessary action” would be taken.

“The bodies recovered at the scene were burnt beyond recognition,” Onyango said.

The government said the dormitory was overcrowded, in violation of safety standards.

Maina Muthungu, the uncle of a missing student, told Al Jazeera: “We need to know the truth however bad it is. We want to know who is alive and who is not. They are not telling us anything.”

The primary boarding school has a total of 824 students – 402 boys and 422 girls, the Ministry of Education said in a statement on social media platform X.

Of them, 156 boys and 160 girls are boarders while the rest are day scholars.

The school is located about 170km (106 miles) north of the capital, Nairobi.

“All relevant government agencies have been deployed … [to] seek the truth on what caused the fire leading to the loss and injury of so many young souls,” Interior Minister Kithure Kindiki said after visiting the school.

“The government assures full accountability for all whose action or inaction contributed to this tremendous loss,” Kindiki wrote on X.

Police and forensic analysts were at the site while health agencies and the National Disaster Operation Centre were offering aid and counselling services to parents and the school community, the Ministry of Interior said.

The government was also reviewing the security management of schools.

President William Ruto called the news “devastating” and said action would be taken against those responsible.

“I instruct relevant authorities to thoroughly investigate this horrific incident. Those responsible will be held to account,” he wrote on X.

Ruto declared three days of mourning, starting from Monday, during which flags will be flown at half-staff.

The Kenya Red Cross said it sent medical supplies to treat burns and that the injured children were taken to Nyeri Provincial General Hospital.

In a statement on X, it said the scene was cordoned off by police.

“The Kenya Red Cross is providing psychosocial support services to the pupils, teachers and affected families and has set up a tracing desk at the school.”

Fires are common in Kenyan boarding schools, where many students stay because parents believe it gives them more time to study and precludes long commutes.

Some of them have been caused by arson attacks.

Nine students were killed in 2017 in a fire at a school in Nairobi that the government attributed to arson.

In 2016 also, nine students were killed by a fire at a girls’ high school in the Kibera neighbourhood of Nairobi.

Eight students were killed in 2012 at a school in Homa Bay County in western Kenya.

In 2001, 58 pupils were killed in a dormitory fire at Kyanguli Secondary School outside Nairobi.