ABUJA, Nigeria (AP) — Nigerian troops rescued seven children and two women abducted by gunmen at an orphanage last month in a north-central region, the army said in a statement released Thursday.

Authorities in Nigeria's Kogi state said that gunmen attacked an Islamic orphanage that was operating illegally and abducted 23 pupils in an “isolated area” of Lokoja, capital of Kogi State, on April 26. Fifteen of those abducted were immediately rescued.

The troops intercepted and recovered nine of those abducted within a forest area in the state, army spokesman Hassan Abdullahi said in the statement, which was dated Wednesday but released on Thursday.

“The rescued victims comprised five boys, two girls, and two adult females, believed to be the wives of the proprietor of the orphanage,” Abdullahi said.

The development would mean that there could be one more pupil missing, but the statement didn't mention if anybody else was unaccounted for.

No group has yet claimed responsibility for the attack. Armed groups attack schools and abduct students because they are seen as strategic in drawing attention and exacting huge ransoms, according to analysts. Several hundred students have been kidnapped across Nigeria.