NAIROBI, Kenya, Sept 7, (AP): A fire in a school dormitory in Kenya has killed 18 students and 27 others have been hospitalized, with 70 children unaccounted for, the country’s deputy president said Friday. President William Ruto declared three days of mourning during which flags will be flown at half-staff in honor of the children who died.

Deputy President Rigathi Gachagua said only 86 out of more than 150 children had been accounted for, and urged community members who may have sheltered some of them to help account for them. Gachagua said that one more student had died at the hospital and that 37 pupils had been reunited with their parents so far.

The cause of the fire Thursday night at Hillside Endarasha Primary school in Nyeri County was being investigated, police spokesperson Resila Onyango said. The school serves children up to the age of 14. Nyeri County Commissioner Pius Murugu and the education ministry reported that the dormitory that caught fire housed more than 150 boys between ages 10 and 14. Since most of the buildings are made from wooden planks, the fire spread quickly.

The mixed day and boarding private school, which has 824 students, is located 200 kilometers (125 miles) north of the capital, Nairobi, in the country’s central highlands, where wooden structures are common. Nyeri County Gov. Mutahi Kahiga told journalists that rescue efforts were hampered by muddy roads caused by rains in the area.