The Indigenous People Of Biafra (IPOB), an outlawed group, was suspected of carrying out the attack, the spokesperson, Mohammed Yerima, said in a statement.

One of the killed, identified as Joseph Nnachi, a senior member of the IPOB, had been "organizing attacks against security agencies and government establishments" in the country's troubled southern region, according to Yerima.

Another member of the IPOB was arrested, Yerima said, adding that "he has been assisting security forces with useful information."

The southern part of Nigeria has seen a series of gunmen attacks on security formations like police stations and prisons in recent months.