Boko Haram Islamists have invaded the restive northeast Nigerian city of Gombe, firing heavy guns and throwing leaflets calling on residents to boycott upcoming general elections.
The governor of Gombe state imposed an around-the-clock curfew after Saturday's attack, his spokesman said.
"Governor Ibrahim Dankwambo has directed that a 24-hour curfew be imposed on Gombe as a result of the security breach in the city," Ayuba Aluke told AFP, referring to the state capital of the same name but specifying that the curfew would be in effect statewide.
"By this announcement residents are to remain indoors until further notice as security operatives work to restore law and order in the city," he said.
Locals say hundreds of Boko Haram gunmen invaded the city on Saturday morning.
"The Boko Haram gunmen are now at the Jeka-da-Fari roundabout in the centre of the city, firing indiscriminately and throwing pamphlets calling on people not to participate in the elections," resident Ali Dahiru said.
Witnesses said the extremists advanced without any resistance from the security forces.
A Nigerian fighter jet encircled the city but made no attempt to attack the insurgents, said witness Kabiru Na-Gwandu.
"I received calls from friends in Kwadam, which is five kilometres away, warning me to leave because Boko Haram were on their way," said Na-Gwandu, who lives near the military base in the city.
"I evacuated my house along with my family before they arrived in the city and I'm happy that I did because from information I'm receiving they have taken over the military barracks," he said.
The Boko Haram fighters appealed to residents to boycott the elections which had originally been planned to take place on Saturday before they were postponed until March 28.
Gombe has been repeatedly hit by suicide attacks and other bombings blamed on the Islamists in the six-year insurgency in Nigeria's northeast.
In the past few weeks, the group has stepped up its offensive both within Nigeria and against border towns of neighbouring countries, forcing Nigerian general elections that were scheduled for Saturday to be postponed by six weeks.
On Friday, Boko Haram fighters attacked Chad for the first time, targeting a village on the shores of Lake Chad.
The attack marked a new escalation in the group's bloody six-year campaign to establish a hardline Islamic caliphate in northeast Nigeria, which borders Cameroon, Chad and Niger, a campaign that has killed some 13,000 people since 2009.
Nigeria, Cameroon, Chad and Niger this month launched an unprecedented joint effort to crush the Islamists, raising hopes that the insurgents - who have outgunned Nigeria's national army - might finally have met their match.
