Boko Haram has claimed a series of recent attacks in Africa's most populous nation and top oil producer, including coordinated gun and bomb assaults on January 20 in Kano, Nigeria's second city, that killed at least 185.
A senior police officer told AFP the police station in Kano's Sharada neighbourhood had been burned down by attackers armed with explosives, who also shot one officer in the leg.
News that makes sense
Your trusted source for staying up-to-date with the world around you. Get free daily news updates and analysis, straight to your inbox.
There was also a shootout between police and the attackers, residents said.
"I had just arrived home in time for the curfew when I heard an explosion coming from around the police station. Shortly, gunshots followed. From what I heard it sounded like a shootout," said Bala Salisu, 46, from Kano's Sharada district.
Authorities imposed a dusk-to-dawn curfew in Kano following the January 20 attacks that primarily targetted the police, like many of the group's recent assaults.
Another Kano resident, Sadiq Aniyu, said he was at a checkpoint not far from the police station when he "heard a huge explosion and gunshots."
"We all panicked and it became chaotic as people on cars and on motorbikes jostled to escape the area," Aniyu, 30, said.
Residents reported a separate gunbattle near a suspected Boko Haram hideout on the outskirts of Kano, the predominantly Muslim northern hub.
A joint military and police force raided a home in the Mariri neighbourhood sparking a shootout with the occupants, said locals who requested anonymity.
Separately in Maiduguri, east of Kano, residents reported multiple blasts at the Gamboru market that set several vehicles and shops on fire.
Maiduguri is seen as a stronghold of Boko Haram, the shadowy Islamist group blamed for a series of recent attacks in Nigeria that have killed more than 200 people already this year.
"I heard five explosions around the market and plumes of black smoke... filled the air. The market is still on fire. Soldiers and policeman have taken over the whole area," said resident Aisha Goni.
Colonel Victor Ebhaleme, operations chief for the Joint Task Force in Maiduguri, a special military unit set up to crack down on Boko Haram, confirmed the explosions at the market but declined to give details.
Security forces have faced mounting pressure to contain the Boko Haram insurgency that has involved a set of increasingly sophisticated attacks.
The spiralling violence has sparked deep concern in the international community and shaken the country, whose 160 million population is roughly divided between a mainly Muslim north and predominantly Christian south.
There has been intense speculation over whether Boko Haram has formed links with outside extremist groups, including Al-Qaeda's north African branch.
Analysts say the violence has been fed by deep poverty in the north, where masses of unemployed youths have little trust in government or hope for the future in a country long considered one of the world's most corrupt.
