At least 20 nursery-school children died in Niger on Tuesday in a fire that trapped them in straw-hut classrooms in a school in a poor neighborhood of the west African nation's capital, government officials said.

"There were 20 deaths, most of them young children," said the head of Niger's fire service, Colonel Bako Boubacar. He said the origin of the fire in Niamey was unknown.

An official of a Niger's teachers union said the school in the popular Pays Bas neighborhood had around 800 students, including children in the nursery section.

"The fire apparently started around the school gate. Without an emergency exit, many were trapped and students were forced to scale the wall to escape. Those that died were mostly children in the preschool," Mounkaila Halidou said.

Another fire service official said 21 straw hut classes caught fire during the blaze and the children were trapped inside them. (Reuters via VOA)

*PHOTO CAPTION: PEOPLE WALK IN A COURTYARD IN NIAMEY NIGER, A FIRE AT A SCHOOL IN PAYS BAS NEIGHBOURHOOD ON TEUSDAY LEFT AT LEAST 20 CHILDREN DEAD