Twenty bodies bearing fresh wounds were prepared for burial at the Jos central mosque as troops sent to restore calm received orders to shoot any troublemakers on sight.
Authorities imposed an around-the-clock curfew in the hardest-hit areas of the central Nigerian city, where traditionally pastoralist Hausa Muslims live in tense, close quarters with Christians from other ethnic groups.
The fighting began as clashes between supporters of the region's two main political parties following the first local election in the town of Jos in more than a decade. But the violence expanded along ethnic and religious fault lines, with Hausas and members of Christian ethnic groups doing battle.
The hostilities mark the worst clashes in the restive West African nation since a 2006 outbreak left 127 people dead.
Angry mobs gathered Thursday in Jos after electoral workers failed to publicly post results in ballot collation centers, prompting many onlookers to assume the vote was the latest in a long line of fraudulent Nigerian elections.
Riots flared Friday morning and at least 15 people were killed in the violence. Local ethnic and religious leaders made radio appeals for calm on Saturday, and streets were mostly empty by early afternoon.
Jos, the capital of Plateau State, has a long history of community violence that has made it difficult to organize voting. Rioting in September 2001 killed more than 1,000 people.
The city is situated in Nigeria's "middle belt," where members of hundreds of ethnic groups commingle in a band of fertile and hotly contested land separating the Muslim north from the predominantly Christian south.
The latest violence is the worst since the May 2007 inauguration of President Umaru Yar'Adua, who came to power in a vote that international observers dismissed as not credible.
Few Nigerian elections have been deemed free and fair since independence from Britain in 1960, and military takeovers have periodically interrupted civilian rule.
More than 10,000 Nigerians have died in sectarian violence since civilian leaders took over from a former military junta in 1999. Political strife over local issues is common in Nigeria, where government offices control massive budgets stemming from the country's oil industry.
Associated Press Writer Bashir Adigun in Abuja, Nigeria, contributed to this report.