Coordinated bomb attacks targeting security forces and gun battles have killed at least 28 people and spread chaos in Nigeria's second-largest city, with bodies littering the streets on Saturday, Jan 21, AFP reported.

A 24-hour curfew was also imposed on the city of Kano, the largest in Nigeria's mainly Muslim north and which exploded into violence on Friday evening, with eight police and immigration offices or residences targeted.

The main newspaper in Nigeria's north reported that a purported spokesman for Islamist group Boko Haram had claimed responsibility for the violence, saying it was in response to authorities' refusal to release their members from custody

According to AP, in a statement issued late Friday, federal police spokesman Olusola Amore said attackers targeted five police buildings, two immigration offices and the local headquarters of the State Security Service, Nigeria's secret police.

"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," Amore said. Police are "appealing to members of the public to come forward with information on the identity and location of these hoodlums. Information given will be treated with utmost confidentiality."