A series of coordinated bomb attacks targeting security forces and gunfire in Nigeria's second-largest city Friday killed at least eight people, including a suicide bomber at a police office.
The city of Kano, the largest in Nigeria's mainly north, erupted in chaos, with some 20 explosions heard and gunfire ringing out as eight police and immigration offices or residences were targeted.
It was not immediately clear who was behind the violence, though previous such attacks in Nigeria's north have been blamed on Islamist group Boko Haram.
Police confirmed eight areas had been targeted, including state police headquarters and a regional police base. A secret police office was also hit along with a passport office and immigration building.
"The police have commenced investigation and therefore use this medium to call for calm among the residents of Kano as police are doing their best to bring the situation under control," a statement said.
It labeled the attackers "hoodlums" and spoke of seven casualties. Police spokesmen gave varying explanations of whether the statement meant seven were killed or if some were wounded.
The shocking attacks, with Kano having escaped the worst of the violence blamed on Boko Haram in recent months, left residents fleeing neighbourhoods and fearing what would come next.
Those killed included a local journalist, three police officers, three immigration officers and a suicide bomber, various sources said. The state government imposed a 24-hour curfew until further notice.
"We have lost three of our men in the attack," said local immigration spokesman Mohammed Kanoma.
"They were personnel at the passport office. They were shot dead by the attackers during the attack on a nearby police station."
A senior police source said the suicide blast occurred at a regional police headquarters, adding three officers and the bomber died. A journalist for local Channels TV was also reported killed.
"Scary. Multiple explosions at different spots targeting security agencies in Kano today," Yushau Shuaib, spokesman for the National Emergency Management Agency said in a text message.
"Rescue workers evacuating victims to hospitals. No official casualty figures for now."
An emergency official in Kano said he was trying to access affected areas, but roads were blocked.
"There are so many of these heavy blasts around the town," said Abubakar Jibril.
A Red Cross official said it was not safe for them to go out into the city.
An AFP journalist heard what sounded to be some 20 explosions coming from at least two neighbourhoods in the city. Smoke could be seen billowing from the areas.
The loud explosions caused chaos, with motorcycles and cars fleeing the areas.
"It's terrifying where we are now," one resident said. "Bombs are going off inside the police headquarters, and then shootings between police and some gunmen."
A resident in Marhaba district told of a fierce gun battle, adding: "Now my dress is drenched in blood because I had to help carry someone shot in the shootout."
President Goodluck Jonathan declared a state of emergency on December 31 in parts of four states hard hit by attacks blamed on Boko Haram.
Kano is not included in the state of emergency and has not been hit by any of the recent major attacks, most of them having occurred in the country's northeast.
Nigeria, Africa's most populous nation and largest oil producer, is roughly divided between a mainly Muslim north and predominately Christian south.
The state of emergency has not stopped attacks, and the areas targeted have spread beyond the locations covered by the decree.
The limitations of the Nigerian authorities were recently highlighted when the alleged mastermind of a Christmas day attack outside a church that killed 44 people escaped police custody in suspicious circumstances.
Attacks specifically targeting Christians have also given rise to fears of a wider religious conflict in the country, with Christian leaders warning they will defend themselves. Some have even evoked the possibility of civil war.
However, attacks blamed on Boko Haram have included a wide range of targets.
The group also claimed responsibility for the August suicide bombing of UN headquarters in the capital Abuja that killed 25 people.