Boko Haram militants in northeast Nigeria have sent out four times as many child suicide bombers this year as they used in all of 2016, the United Nations Children's Fund says.
Eighty-three children had been used as bombers since January 1, 2017, UNICEF said.
Of those, 55 were girls, mostly under 15 years old and 27 were boys. One was a baby strapped to a girl. Nineteen children were used last year, UNICEF said.
The Boko Haram insurgency, now in its eighth year, has claimed over 20,000 lives and forced more than two million people to flee their homes over eight years.
The frequency of suicide bomb attacks in northeastern Nigeria has increased in the past few weeks, killing at least 170 people since June 1, according to a Reuters tally.
UNICEF, in a statement released on Tuesday, said it was "extremely concerned about an appalling increase in the cruel and calculated use of children, especially girls, as 'human bombs' in northeast Nigeria. The use of children in this way is an atrocity".
Boko Haram is trying to create an Islamic state in the Lake Chad region, which spans parts of Nigeria, Niger, Cameroon and Chad. It gained notoriety by abducting more than 200 girls from the northeast Nigerian town of Chibok in April 2014.
