MAIDUGURI, Nigeria: Boko Haram Islamists attacked a military base in the northeast Nigerian city of Maiduguri on Friday and freed dozens of insurgents from custody, the military said of the latest raid in the embattled city.
Before storming the Giwa barracks, a notorious prison for Islamist fighters, the gunmen opened fire in a residential neighbourhood and razed many homes, witnesses said.
The attack is another blow to the military's campaign against the extremist group, which has been blamed for thousands of killings since 2009 in Africa's most populous country and top oil producer.
An AFP reporter near the Giwa barracks said the shooting there started shortly after 7:00 (0600 GMT).
Gunmen hurled explosives into the compound, causing several buildings to catch fire, witnesses said.
A military source who requested anonymity told AFP that the insurgents forced their way inside the barracks prison and "freed dozens of their members".
Asked about the report, defence spokesman Chris Olukolade told AFP that "many insurgents are in flight. Whether they were those who staged the attack or those who were held prisoner is not yet known."
In a separate statement, Olukolade said the insurgents have been hit hard by military bombardments in recent weeks and Boko Haram attacked the barracks "to boost their depleted stock of fighters."
The insurgents have previously carried out a number of prison breaks, but this appeared to be the most dramatic in many months.
The northeast has been under a state of emergency since May when the military launched a major offensive aimed at crushing the Islamist uprising.
Defence officials have sought to portray the operation as a success but the violence has continued unchecked.
Human Rights Watch on Friday said Boko Haram had carried out more than 40 attacks already in 2014, with more than 700 people killed, one of the highest rates of killing since the uprising began.
Many of those attacks have targeted defenceless civilians in remote villages, leading to claims from the military that the insurgents were no longer capable of striking anything but soft targets.
But the latest daring raid in Maiduguri, which followed a similar attack in the city in December on the military and the airport, has re-enforced the notion that Boko Haram is still able to hit heavily fortified targets.
According to multiple witness accounts, the gunmen entered Maiduguri after crossing a river on the fringes of the city, then passed through the residential neighbourhood of Fauri.
They fired on civilians, witnesses said, but details on casualties were not immediately available.
Students at the University of Maiduguri, which is near the barracks, reported hearing sustained gunfire throughout the morning, but there was no indication that students were specifically targeted.
"There have been several deafening explosions and unending gunfire for the past one hour," student Mercy Bitrus told AFP earlier on Friday.
According to the defence spokesman, the Islamists staged the attack in response a series of military operations launched across the northeast in recent days.
Those operations have destroyed Islamist camps and "killed many insurgents", Olukolade said.
As the violence persists, rights groups and rescue agencies have raised the alarm about the condition of those caught up in the conflict.
The UN has said that nearly 300,000 people have fled their homes since emergency rule was imposed in May and are struggling to access relief materials because of the unrest.
"Even if the government cannot stop the attacks, at the very least it can meaningfully assist the people who have been most devastated by them," said Daniel Bekele, Africa director at Human Rights Watch.