A photograph taken on September 8, 2010 shows prison staff members outside the partly scorched exterior of the central prison in the northern Nigerian city of Bauchi after 200 Boko Haram militants stormed the prison and freed 173 of their comrades.
Unknown assailants have stormed a federal prison in central Nigeria with heavy gunfire and explosives before killing one the wardens and emptying the jail of its 200 inmates.
"There was a jail break last night. From reports available to us, a large number of gunmen attacked the Koton Karfe prison at around 7:00 p.m. local time (1800 GMT) and threw explosives at the gate and opened fire on our wardens," prison spokeswoman Hadiza Aminu said on Thursday. She said a shootout then erupted.
"One of our men was killed and the gunmen overpowered the wardens and broke into the cells, freeing inmates -- 199 inmates all awaiting trial escaped, leaving only one inmate," Aminu told AFP.
She refused to speculate on the identity of the attackers.
"We still don't know who was behind this attack. Investigations have commenced to determine that,” Aminu said.
Nigeria Prisons Service spokesman Kayode Odeyemi said the prison held armed robbers and kidnappers.
He said he did not know if the prison held any members of the militant group Boko Haram.
However, a local resident Isiaka Yakub said, "From all indications, the attackers were members of Boko Haram." He added that there were about 20 militants attacking the jail.
Boko Haram has been blamed for series of gun and bomb attacks in several parts of Nigeria in recent months.
Boko Haram launched a similar massive prison break in Bauchi state in September 2010 that freed about 700 inmates there.
Wednesday’s prison attack had all the hallmarks of that previous assault by the sect.