MAIDUGURI, Nigeria (AP) — A top Boko Haram commander was among many insurgents killed Sunday as soldiers fought to rescue nine children being trained at a secret camp, a Nigerian official said Monday.

Soldiers on their way to an Islamic extremist camp in Jarawa village in Borno State ran into an ambush by Boko Haram fighters, said Nigerian army spokesman Brig. Gen. Sani Usman. The soldiers then killed a large number of Boko Haram insurgents, including one of its commanders, Abu Nazir, who was on the military’s wanted list, Usman said.

Soldiers also rescued nine abducted children, who are now being given preliminary humanitarian assistance. They will then go to a displaced-persons camp in Kala Balge, about 150 kilometers (93 miles) west of Maiduguri, the Borno state capital, the army spokesman said.

Boko Haram sometimes uses kidnapped girls and boys to carry out suicide attacks.

Also Monday, soldiers arrested 24 suspected Boko Haram members in Edo state in southern Nigeria, said a local leader.

Alhaji Aliru Momoh, the leader of the Auchi Kingdom, said the Boko Haram members were posing as Fulani herdsman when they were arrested. More than 400 people have lost their lives in clashes between suspected Fulani’s herdsmen and local farmers in North Central states of Nigeria in the past two years.

Alhaji Momoh said “the traditional council is collaborating with security agencies and some” local civilian defense force groups to address the issue of militants fomenting violence there.

Boko Haram’s eight-year insurgency has killed more than 20,000 people.