The UN’s children’s charity, Unicef, says children were used as suicide bombers in a triple suicide attack in Borno, north-east Nigeria on Sunday.
At least 30 people were killed and over 40 were injured in the attack.
Unicef says multiple reports say the attack was carried out by a boy and two girls. Their ages are not yet known.
The attack happened outside a hall where people were gathered to watch television in the town of Konduga.
According to Unicef, five children have been used in suicide attacks since the beginning of the year.
In 2018, 48 children were used as human bombs, including 38 girls.
President Muhammadu Buhari has commiserated with the families of the victims and promised to bring the perpetrators to justice.
The attack is believed to have been carried out by the Boko Haram jihadist group which has been operating in the region for a decade.
Although it has lost territory to the Nigerian armed forces, the group still carries out regular attacks in the north-east.