NAIROBI, Kenya (AP) — Officials began removing the bodies of children who burned to death in a school dormitory in central Kenya on Sunday as they tried to account for dozens of boys who are still missing.

Journalists were moved to wait outside the school compound as a team that included morticians from the Nyeri provincial hospital set up tables outside the dormitory on Saturday.

Eighteen boys aged between 10 and 14 are known to have died and 27 were hospitalized after the Thursday night fire at Hillside Endarasha Primary school, but 70 others are still unaccounted-for.

The country's president, William Ruto, has declared three days of mourning. Police are still investigating the cause of the fire.

Anxious parents who had been waiting all day for news about their children were on Friday evening allowed to see what remained of the dormitory. Some parents broke down as they left the scene.

The government has urged school administrators to enforce boarding guidelines that require dormitories to be spacious, with three doors and no grills on the windows for easy escape in case of fires.

School fires are common in Kenyan boarding schools, often caused by arson fueled by drug abuse and overcrowding, according to a recent education ministry report. Many students board because parents believe it gives them more time to study without long commutes.

Some fires have been started by students during protests over the workload or living conditions. In 2017, 10 high school students died in a school fire in Nairobi started by a student.

Kenya’s deadliest school fire in recent history was in 2001, when 67 students died in a dormitory fire in Machakos county.