A grenade blast killed at least three children and wounded another five in Nigeria's volatile northeast town of Ngala.

In a statement, the UN agency said the children playing on Mblu Bridge in Ngala, a town near the Cameroon border, were killed by “unexploded remnants of war.”

Government troops and the Boko Haram terrorists fought pitched battles in the town between 2015 and 2018.

“Three children have sadly lost their lives, three others are in critical conditions while two other children sustained mild injuries,” the global body said.

Peter Hawkins, a UNICEF representative in Nigeria, warned no children should fall victim to unexploded remnants of war while playing.

He said thousands of children have been killed, maimed, abducted, or displaced over a decade of terror attacks in the West Africa country's northeast region.

Boko Haram has been carrying out violent attacks on civilians in vulnerable communities and military bases in the region since July 2009./aa