More than 1,800 inmates have escaped from a prison in Nigeria after it was attacked by gunmen, officials reported.
Gunmen stormed the prison in the south-eastern city of Owerri after blasting their way in with explosives.
It was among a series of coordinated assaults launched in the early hours of Monday, which also targeted police and military facilities in the capital of Imo state.
The attacks come less than two weeks after a previous wave of violence in the south-eastern part of the country, when at least a dozen security officers were killed during assaults on four police stations, military checkpoints and prison vehicles.
Police have accused the banned separatist group, the Indigenous People of Biafra, of carrying out the attack. It has reportedly denied involvement.
The Nigerian Correctional Service has confirmed that 1,844 inmates escaped from the jail in Imo state.
A police spokesperson said the attackers carried rocket-propelled grenades, machine guns, explosives and rifles.
President Muhammadu Buhari called the attack an "act of terrorism" carried out by "anarchists". He called upon security forces to capture the attackers and the escaped prisoners.
A spokesman for the Indigenous People of Biafra separatist movement told the AFP news agency that accusations it was behind Monday's attack were "lies".
Imo state has long been a breeding ground for separatist groups, while relations between the central government and indigenous Igbo population are strained.
Meanwhile, large amounts of ammunition was stolen in the raids for which no group has claimed responsibility.
It is among a number of serious security challenges facing President Muhammadu Buhari, including a decade-long Islamist insurgency in the northeast, a spate of school kidnappings in the northwest and piracy in the Gulf of Guinea.