| Boko Haram is waging a low-level campaign against the Nigerian government, which it says is corrupt [Reuters]
A blast has rocked an area near a military barracks in the northern Nigerian city of Kaduna but the cause of the explosion and the number of casualties are still not clear, according to an official.
Residents said Tuesday's incident occurred in the area of a military barracks known as the First Mechanised Division and that windows in an office complex there were shattered.
"NEMA rescue team alerted to explosion at military formations in Kaduna," Yushau Shuaib, a spokesman for the National Emergency Management Agency, said in a brief statement.
"Yet to confirm the nature of explosion or casualty. Relevant security working to contain the situation."
The area has been cordoned off, but the office complex could be seen, residents said. "Virtually all the glass has been shattered," one resident said.
"I saw soldiers with glass cuts on their bodies being taken out, but it's difficult to say if there were any [more serious] casualties."
Boko Haram, a radical Islamist group, has been blamed for scores of bomb attacks in northern Nigeria.
The group is waging a low-level campaign against the government and says it wants to impose Islamic law across the country of 160 million people split evenly between Muslims and Christians.
An army source said earlier on Tuesday that security forces had killed eight suspected Boko Haram members in a raid on an alleged hideout of the group in Kano that prompted a five-hour shootout.
The raid, on the outskirts of Nigeria's second city, was carried out Monday evening as the attackers, believed to be Boko Haram members, bombed a police station in another city neighbourhood, where they also shot an officer in the leg.
"The military succeeded in killing eight gunmen, arrested five others and discovered five high-calibre bombs and 15 other low-calibre bombs. All these are homemade," the military source, who requested anonymity, said
Residents who visited the alleged Boko Haram hideout in Kano's Mariri neighbourhood told the AFP news agency that parts of the floor were blood-stained.
The military source said some attackers escaped during the raid and that security forces found a large cache of guns and ammunition inside.
"The first indications are that this is an armoury for the sect," the source said.