The African militant group Boko Haram is increasingly using children to carry out suicide bombings.
The United Nations says 44 children were involved in Boko Haram suicide attacks last year. Only four children were used in such attacks in 2014.
The information comes from the UN Children's Emergency Fund, known as UNICEF.
A UNICEF report said that 20 percent of Boko Haram suicide bombers were children. The youngest was thought to be eight years old.
The militant group has sent children to carry out attacks in crowded markets and religious centers. The children sometimes do not know they are carrying explosives. The boys and girls are rarely considered as a threat by police or security forces.
Over the past two years, UNICEF said, Cameroon alone has recorded 21 suicide attacks involving children. Nigeria has 17 such attacks, while Chad has two.
The report was released on the second anniversary of Boko Haram’s kidnapping of 276 girls from Chibok in northern Nigeria. Among those, 219 are still missing.
Women and girls freed from Boko Haram say the militants used them as sex slaves or forced them to assist in the group’s operations.
Boko Haram’s seven-year campaign of violence has killed 20,000 people and displacedmore than 2 million others.
The group set out to establish its version of Islamic law in northern Nigeria. That has included launching war on Western education. Human Rights Watch reported Tuesday that Boko Haram has killed 611 teachers since 2009. Attacks have destroyed or led to the closure of over 2,000 schools.