Another police station attacked in Nigeria's restive southeast

Gunmen have stormed another police station in southeast Nigeria and freed prisoners there, police and local media said Wednesday, after the region was hit by a massive prison breakout blamed on separatists.

The police station in the town of Ehime Mbano in Imo state was set ablaze on Tuesday after it was raided by the gunmen, police spokesman Orlando Ikeokwu said.

"I can confirm to you that another police facility was attacked by bandits," Ikeokwu told AFP.

Three vehicles were burned, he said, but he did not say if there were any casualties. Local media said some detainees were freed by the gunmen.

Southeast Nigeria has seen an upsurge in attacks targeting security forces in violence that officials blame on the Indigenous People of Biafra (IPOB), a separatist group seeking independence for the indigenous Igbo people.

The Ehime Mbano attack came a day after gunmen using rockets and explosives raided a prison and the police headquarters in Imo's state capital Owerri at dawn on Monday, freeing more than 1,800 inmates.

Prison officials said as of Wednesday, 48 escaped Owerri inmates had been recaptured, had returned on their own or been handed over by their families, religious leaders or traditional rulers.

IPOB has denied accusations it carried out the prison attack, but the police declared a clampdown on the outlawed group.

Map of Nigeria locating the Owerri prison. By (AFP)

The armed forces said Wednesday a joint security operation was underway in the volatile region "to flush out the miscreants".

Vice President Yemi Osinbajo visited Imo state on Tuesday to assess the damage in Owerri.

"Anyone who perpetrates violence does not represent the progressive-mindedness of the good people of this state and this zone," Osinbajo said.

"And I call on all of us to come together to resist any attempt to turn the progress and peace that this zone is set to experience to conflict and disruption."

Calls for a separate state of Biafra in the south are a sensitive subject in Nigeria, after a unilateral declaration of independence in 1967 sparked a brutal 30-month civil war.

More than one million people died, most of them Igbos, from the effects of conflict and disease.

Unrest in the southeast is just one security challenge facing President Muhammadu Buhari's security forces. They are also battling a more than decade-long jihadist insurgency in the northeast, and mass kidnappings for ransom and banditry in the northwest.