Ten Tanzanian schoolchildren were killed when a dormitory at a privately-owned primary school in the north of the country caught fire, a senior government official said on Monday, Reuters reported.

Police, the fire department, and other government officials have started an investigation into the fire, the cause of which is unknown, said Marco Gaguti, the regional commissioner for Kagera.

“This dormitory was housing 74 pupils and when it caught fire the pupils started fleeing, but due to the impact of the fire some couldn’t make it on time,” Gaguti said.

Seven other children suffered from burns during the inferno, which started before midnight.

Police are working with relatives of the pupils to identify the charred bodies, Gaguti said, adding that investigators are expected to establish the source of the fire in the next 14 days.