KANO, Nigeria, June 4, 2025 (BSS/AFP) - Eleven children were buried alive while excavating sand in northern Nigeria when a pit collapsed on Tuesday, police said.

The children, aged between four and nine, were excavating sand for making mud bricks when the pit outside Yardoka village in Kaduna state collapsed on them.

"Eleven of the children died and seven others were injured and now in hospital receiving treatment," Mansir Hassan, Kaduna state police spokesperson said.

"Our men and volunteers from the village dug out the victims from the collapsed pit."

Police are investiging whether the children were recruited to work, which would be considered child labour, Hassan said.

The children were from an informal madrassa, or Islamic religious school, which are common in predominantly Muslim northern Nigeria.

Children from poor backgrounds are often sent to madrassas to learn the Koran, and many beg in the streets or take on menial jobs to pay the school fees.

Attempts by authorities and local groups to reform the age-old madrassa system have faced opposition from traditional clerics.

In February, 17 pupils were killed and 17 others were severely injured when a fire tore through the lodging of a madrassa in northwestern Zamfara state, according to police.