LAGOS, Nigeria (AP) _ Ethnic rioting, which killed at least 36 people last weekend in the southwest, on Thursday spread to northern Nigeria, witnesses said.

Riot police used tear gas to disperse about 500 youths from the Hausa group who chanted war songs as they descended on a section of the city of Kano dominated by Yorubas, according to local reporters.

Later, the rioters ran through the streets, throwing stones at police. Several people were injured, the journalists said.

Nigeria is sharply divided along ethnic and religious lines and is often torn by violence.

Emotions had been running high in Kano since members of the Hausa group, fleeing the weekend clashes in the southwest city of Sagamu, began arriving in town.

Authorities said the fighting in Sagamu began when Yorubas participating in a traditional masquerade festival came across a pair of Hausa prostitutes and attacked them.

The city was quickly overrun by roving bands of Yorubas and Hausas, who attacked one another and passers-by and burned buildings.

The Yorubas, a mostly Christian tribe, dominate Nigeria's southwest. The Hausas are from the country's Muslim north.