At least 13 people died in rioting in the northern Nigerian city of Kano.

Nigeria's army is restoring an uneasy calm to the country's largest Northern city.

The fighting between Christians and Muslims was apparently fuelled by clashes during a protest against the bombing of Afghanistan.

Hundreds of soldiers were deployed in an anxious bid by authorities to restore order and prevent an escalation of the fighting.

It is latest violence in a cycle of bloodletting since a dozen northern states began introducing Islamic law, or Shariah, last year.

Although Kano, northern Nigeria's largest city with several million inhabitants, is overwhelmingly Muslim and ethnic Hausa it also attracts a significant number of non-indigenous Christian traders who come to the city to trade consumer, agriculture and industrial goods.

Police say 13 people are confirmed dead, including five rioters shot by police. There are unconfirmed reports of many more dead. Police made more than 100 arrests.

The offices of many Nigerian newspapers are among the businesses looted and destroyed. The roof of the office of Lagos-based ThisDay newspaper was caved in.

Three churches were at least partially-burned and a mosque was also torched, witnesses say.