More than 1,800 prisoners escape after attack on Nigeria jail

More than 1,800 inmates have escaped after heavily armed men attacked a prison in southwest Nigeria using explosives, according to prison authorities.

The attackers blasted their way into the Owerri prison in Imo state, engaging guards in a gun battle, the national corrections authority said in a statement.

The gunmen also destroyed the State Police Command headquarters in Owerri, the capital city of the state, and burnt down almost 50 vehicles parked at the main office, a witness told Anadolu Agency.

"I can confirm that the Imo State command of the Nigerian Correctional Service was attacked by unknown gunmen in Owerri," Imo state corrections service spokesman James Madugba told AFP, adding that the number of escaped inmates was yet to be confirmed.

"The situation is under control," he said.

The assailants arrived in pickup trucks and buses before storming the facility, the correction authority statement said.

The attacks in the town of Owerri began around 2 am and lasted for about two hours, according to local resident Uche Okafor. Gunmen also assaulted various other government buildings in Imo state around the same time, authorities said.

The gunmen also destroyed the State Police Command headquarters in Owerri, the capital city of the state, and burnt down almost 50 vehicles parked at the main office, a witness told Anadolu Agency.

READ MORE: Several soldiers, militia fighters killed in Nigeria ambush

Wave of violence

The coordinated attacks come less than two weeks after another wave of violence in southeastern Nigeria.

At least a dozen Nigerian security officers died when four police stations, military checkpoints and prison vehicles came under ambush by gunmen.

Imo state is part of a region that has long been a hotbed for separatist groups and where tensions between federal authorities and the indigenous Igbo population are often high.

READ MORE: Bandits carry out another deadly attack on village in northwestern Nigeria

No immediate claim of responsibility

The Indigenous People of Biafra (IPOB) has recently been posting videos on social media of dozens of its militiamen in training.

But IPOB spokesman Emmanuel Powerful rejected any involvement in the prison attack in a statement sent to AFP, dismissing any accusations as "lies".

There was no immediate claim of responsibility for Monday's assault on the prison, which was built with official capacity of 548 inmates, but was believed to be housing more than 1,500.

READ MORE: Militants attack UN base in Nigeria, trapping aid workers

However, a paramilitary wing of a secessionist movement active in the region has been battling government security forces since December. The Eastern Security Network, or ESN, has said it is fighting for the protection of the Igbo people from foreign armed invaders killing their people.

Uchenna Madu, the leader of a breakaway faction of another secessionist group, condemned the attack on Monday, saying his followers from the Movement for the Actualization of the Sovereign State of Biafra (MASSOB) believe in non-violent struggle.