Gunmen attacked a police station with explosives in southeastern Nigeria on Sunday, a day after a similar attack in which two police officers were killed in the region, police said.
The attacks in southeastern Imo State illustrate the latest violence in the volatile region, where separatist unrest is on the rise.
"Armed men arrived with dynamite in the early hours of the day" and attacked with "part of the police station in Oru but the assault was repulsed," said the spokesman for the police of the state, Michael Abattam, to AFP.
Among the attackers, "four gunmen were neutralized and five IEDs (improvised explosive devices) were recovered," the spokesman added.
He also reported another attack on Saturday in which gunmen attacked a police station in Umuguma outside Owerri, the state capital, with explosives, killing two police officers.
He said gunmen also invaded the residence of George Obiozor, the head of Ohanaeze, the Igbo cultural union, and destroyed part of the building with explosives.
Obiozor was not at home at the time of the attack, he said. "We are on the trail of the attackers with a view to bringing them to justice," he said.
President Muhammadu Buhari on Sunday condemned the attacks, while pledging to end the continuing violence in the region.
"He expresses his sympathy to the police authorities for the loss of men and equipment, and to Professor Obiozor, whom he urged to maintain his commitment to peace and unity," Buhari's office said in a statement.
Southeastern Nigeria, Africa's most populous country, is facing rising violence. More than 100 police and security forces have been killed by gunmen there since last year, according to local media reports.
Authorities frequently accuse the Independence Movement for Indigenous Peoples of Biafra (Ipob) and its paramilitary wing of being behind the violence in the region, a charge the group denies.
Ipob dreams of reviving the defunct Republic of Biafra, whose declaration of independence led to a 30-month civil war between 1967 and 1970. More than a million people, mostly Igbo, died in the conflict, mostly from starvation and disease.