Suspected Boko Haram Islamists attacked police in the northeast Nigerian city of Damaturu, prompting a fierce gunfight with troops, a police officer and residents said Friday.
The gunmen late Thursday stormed the city in coordinated raids, burning at least four police buildings and leaving an unspecified number of casualties, said a senior police officer, who requested anonymity.
"They invaded the city in large numbers in vehicles and on foot from different directions and launched coordinated attacks on police facilities with guns and explosives and engaged soldiers and policemen in a fierce gunfire exchange that continued deep into the night," he said.
"They have succeeded in burning down the police area command, the CID (criminal investigation department), the mobile (police) base and the 'C' Division police station, all located along Gujba Road on the outskirts of the city," he added.
The insurgents started by attacking a military checkpoint outside the city, but were repelled by troop reinforcements, then they attacked police in Damaturu, the source added.
"There are indeed casualties, including a number of the insurgents, but it is difficult to say how many they are", he said.
A resident, Haruna Sadi, said the attacks started around 5:00 pm (1600 GMT) and continued late into the night, forcing residents to stay indoors.
"We didn't sleep last night due to fright and the deafening gun sounds and explosions coming from all over the city, which was apparently under siege from Boko Haram gunmen," Sadi said.
"Everybody is still indoors because of a radio announcement of a 24-hour curfew by the military who request everyone to stay at home as they conduct operations against the gunmen," he said.
Boko Haram has said it is fighting to create an Islamic state in Nigeria's mainly Muslim north.
Violence by the group is estimated to have cost more than 3,600 lives, including killings by the security forces.
Damaturu, capital of Yobe state, has witnessed several deadly attacks by suspected Boko Haram members.