Two people were killed in attacks on two police stations in Nigeria's Imo state. Armed men attacked the police stations with dynamite explosives and freed suspects from detention.
President Muhammadu Buhari said the government is reviewing the security situation in the country's south-east region after the deadly attacks.
He condemned the weekend raids on police facilities and the residence of the leader of a socio-cultural group in the region.
The attackers also set blaze the residence of the leader of Ohanaeze Ndigbo, an Igbo socio-cultural union.
Four of the attackers were killed during a gun battle with police, a police spokesman told the BBC.
President Buhari said the violence was “deeply distressing” and that the security agencies were working to ensure normalcy returns to the region.
He gave no details of the new strategies his government would employ.
The police blame the separatist group, Indigenous People of Biafra (Ipob) for the violence.
The group, which campaigns for a breakaway state in the region, has denied involvement in some previous attacks but has yet to comment on the latest violence.
In the past year, deadly violence in the region has intensified with suspected separatists mainly targeting security facilities and personnel.