Yobe - A series of attacks by suspected Boko Haram Islamists in Yobe state has killed a number of people and destroyed several buildings, residents and authorities said on Friday.
Explosions and gunfire that started late on Thursday shook the city of Potiskum, with residents reporting several schools and a government building burnt, along with a number of dead.
Police said they were seeking to restore calm and clear unexploded bombs on Friday morning, while some of the ordnance continued to detonate.
"There are so many bombs here and there and I can't give you the casualty figure now, because our men are still in the field to restore calm," said state police commissioner Patrick Egbuniwe.
A military source said some houses had been destroyed by homemade bombs and a security checkpoint was attacked, but he could not give a death toll yet.
He said Islamist extremist group Boko Haram was suspected behind the violence.
"I cannot ascertain as of now how many people were killed, apart from the one [suspect] that I know who was shot at the checkpoint," the military source told AFP.
Residents of the city, which has been repeatedly hit by Boko Haram, described heavy explosions and gunfire, with the city under military lockdown on Friday morning as security forces sought to track down the attackers.
Two residents spoke of seeing a number of bodies, while one said several schools were burnt, including an Islamic seminary.
"From where I stand, I can see the local government secretariat completely burned and several shops around it smouldering from last night's attack," one resident said.
Another said that "at least five primary schools, including an Islamic seminary, have been burnt in the attacks."
Violence linked to Boko Haram's insurgency in northern and central Nigeria, including killings by security forces, are believed to have left more than 2 800 people dead since 2009.