Maiduguri - Gunmen on Tuesday launched coordinated attacks on military barracks, a prison and police stations in the northeastern town of Bama, killing 55 people and springing 105 inmates, the army said.
"Heavily armed Boko Haram terrorists" launched the attacks around 5:00 am, said Musa Sagir, the military spokesman in nearby Maiduguri, the Islamist group's cradle and stronghold.
"Some of the gunmen attacked the military barracks but they were repelled," he said.
He said 10 gunmen were killed and one was arrested at the barracks.
"But the gunmen broke into the prison, freeing 105 inmates, and killed all prison warders they could see except those who hid in a store where cooking utensils were kept," Sagir added.
"In these attacks, 55 people including two soldiers, some prison warders, policemen and civilians were killed," he said.
Sagir said in all 14 prison wardens including a senior officer, two soldiers, 22 policemen, four civilians and 13 Boko Haram gunmen were killed in the attacks in Bama.
"The terrorists also attacked and burnt a police barracks, a mobile police barracks, a divisional police station and a clinic," he said.
He said several vehicles were also burnt in the attacks, with the Islamists using grenades.
Local reporters who visited Bama after the attacks said the slain gunmen wore military uniforms for the attacks.
Tuesday's attacks came after 17 people were killed and many houses burnt following a series of attacks by the extremist group in the town on April 25.
Violence linked to Boko Haram's insurgency has left some 3,600 people dead since 2009, including killings by the security forces.
But an attack mid-April in the remote fishing town of Baga near Lake Chad was "unprecedented" according to Human Rights Watch, leaving some 200 people dead and thousands of houses razed.
The Nigerian Red Cross has said that 187 people were killed in the fighting, while an area senator put the death toll at 228.
Before the Baga carnage, the group's deadliest attack yet occurred in Kano in January 2012, when coordinated bombings and shootings killed at least 185 people.
Boko Haram has said its deadly spate of attacks is aimed at creating an Islamic state in northern Nigeria, which is predominantly Muslim while the southern half of the country, Africa's most populous and top oil producer, is mostly Christian.