The so-called Islamic State (IS) group has claimed responsibility for an attack on a prison in Nigeria’s capital in which nearly 900 inmates were freed, including 60 of its members.

Nigerian security forces were continuing their search for at least 400 escaped prisoners who were still at large.

While Nigeria has suffered multiple jailbreaks in recent years, the attack on Tuesday night was the first in the nation’s capital within that period — a development that analysts say points to a “failure of intelligence”.

The Islamic State West Africa Province said in a statement that the attack on the Kuje prison was carried out in 50 minutes by three groups: One attacked the prison’s gate, another stormed the prison and the third blocked the road leading to the facility.

The group said the attack was part of IS’s campaign to free its members from prisons.

Authorities said the group’s members were “very determined” and launched the daring attack on the prison with “very high-grade explosives”.

They killed one prison guard and freed 879 inmates including 64 of their members who authorities believe they had “specifically” come to rescue.

People living near the prison told The Associated Press how the area had been rocked by gunfire and explosions late on Tuesday night.

A worker at a nearby bakery said the explosion “shook the bakery”.

“More than one hour after, I saw many people leaving (the prison) and I even thought it was people that went to enjoy themselves at the bar here,” he said of the casual way the escapees had walked through the streets.

The Islamic State West Africa Province is an offshoot of Nigeria’s Boko Haram group which has waged an insurgency against the Nigerian government for more than a decade.

Since the death of Boko Haram leader Abubakar Shekau in mid-2021, the IS-linked splinter group has sought to strengthen its position in northeast Nigeria and the surrounding Lake Chad basin, though both groups remain united in their fight against the Nigerian government.

Their rebellion has caused more than 35,000 deaths in northeastern Nigeria and displaced an estimated two million people, according to the UN.

Their jihadi insurgency has expanded to the neighbouring countries of Niger, Chad and Cameroon.

The attack on the prison in Nigeria’s capital city showed the severity of the insurgency, experts said.

“For Abuja to be having this kind of attack, it tells you how much our security intelligence has failed,” Confidence MacHarry, from the Lagos-based SBM Intelligence security firm, said.