The city was placed under a night time curfew between 6 pm (1700 GMT) and 6 am to ease tensions that began early Sunday after an argument on the rebuilding of homes destroyed in the November 2008 clashes, residents said.
A Reuters correspondent counted 12 bodies at Jos University Teaching Hospital and at the city's main mosque. There were reports of as many as 20 dead and several houses destroyed.
The fighting has so far been confined to one neighbourhood where Muslims and Christians live side-by-side, a resident said. In November 2008, fighting spread throughout the city and hundreds were killed in two-days of clashes triggered by a disputed election. The fighting was the worst between Muslim and Christian gangs in years in Africa's most populous country.