Gunmen burst into a secondary school in ​Nigeria's northeastern Borno state and abducted students as ‌they were sitting exams on Monday morning, police said, the latest mass kidnapping in an insecure region.

The military said troops rescued 10 students and ​teachers after tracking the attackers and engaging in a ​firefight, in which one soldier and one member ⁠of a paramilitary support force were killed.

Other students were still ​unaccounted for, and officials were trying to work out how ​many were missing, Borno police spokesperson Nahum Kenneth Daso said.

The attackers had fired sporadically as they charged into Government Day Secondary School in the ​town of Lassa in the morning, where students were taking national ​examinations usually sat by 16- and 17-year-olds, Daso said.

The military, police and ‌other security ⁠agencies were searching nearby forests to try to rescue the students, Daso said.

The 10 who were rescued were unharmed and receiving care, while efforts to find others still missing were ongoing, ​military spokesperson Captain ​Mohammed Goni ⁠said.

Nigeria is grappling with overlapping security crises that stretch far beyond the jihadist insurgency in the ​northeast, where Boko Haram and Islamic State ​West Africa ⁠Province (ISWAP) have waged a conflict for more than 15 years.

Borno is the epicentre of the Islamist insurgency, while other parts of ⁠Nigeria ​face mass kidnappings for ransom by ​armed gangs and recurring sectarian violence.