At least five people have been killed after police stations were attacked in the northern Nigerian city of Maiduguri, hospital sources say.
The BBC’s Bilkisu Babangida in the city says there were at least three explosions, while gunfire rang out in what is believed to be the latest attack by the Boko Haram Islamist sect.
Its members have killed dozens of police officers and politicians in the city in the past year.
It wants to overthrow Nigeria’s state.
It believes that Western education is wrong.
In 2009, hundreds of its supporters were killed in Maiduguri after they attacked police stations.
On Monday, the sect was accused of killing a cleric from a different Muslim tradition who had criticised it.
Ibrahim Birkuti was shot dead outside his home in the town of Biu, some 200km (120 miles) south of Maiduguri.
Like previous victims of Boko Haram, he was killed by a gunman riding a motorbike.
Last week, Boko Haram told the BBC it had carried out a series of bombings after President Goodluck Jonathan’s inauguration last week.
A sect spokesman said it was also responsible for killing the brother of the Shehu of Borno, one of Nigeria’s most important Islamic leaders.
The police have made hundreds of arrests and even banned motorbikes at night but have not been able to stop the violence.