Two civilians have died in an attack on a police post in the northern Nigerian city of Kano, police say.
A BBC correspondent says that gunmen stormed the police station, throwing explosives and an hour-long shoot-out ensued.
The gunmen are suspected to be Islamist militants from Boko Haram, which recently carried out multiple bomb attacks in Kano, killing 185 people.
Police say they are also looking into reports of other shootings in Kano.
The BBC’s Abdullahi Kaura Abubakar in Kano says this latest attack on a police station in the Naibawa district happened just before the start of the dusk-to-dawn curfew, which was imposed after the 20 January bombings – the most deadly since Boko Haram began its campaign of violence in 2009.
“We are scared. The police and Boko Haram members are battling each other and there is gunfire everywhere,” local resident Usman Ibrahim Bello told the Reuters news agency.
On Saturday, a Boko Haram spokesman rejected Nigerian President Goodluck Jonathan’s recent call for open dialogue to end the conflict.
He said it was “impossible” to hold talks, after police said they had killed 11 militants in the group’s base in the north-eastern city of Maiduguri over the weekend.