At least 35 policemen are missing after an attack by extremist Boko Haram rebels in a northern Nigeria.
Search efforts have failed to turn up traces of the victims in the attack on the Gwoza city police academy, local media reported on Sunday.
The national police said it was the third attack this month in the strategic north-eastern state of Borno.
Inspector-General Suleiman Abba ordered security tightened around police facilities in the country.
Boko Haram insurgents are seeking to establish an Islamic theocracy in northern Nigeria.
