While there was no serious violence Friday night, some young Muslims threw plastic bottles and cans at the Christians and one poured water on a missionary who said the Muslims were "transgressing against God," the Detroit Free Press reported Saturday.
The Christians have become a regular feature of the festival, held in the largest Arab-American community in the United States, the newspaper said.
Signs carried by the Christians included one that read "Islam is a religion of blood and murder" and another with a drawing of a pig's head.
At least two Christian groups were present Friday. One took a gentler approach, handing out religious literature and urging Muslims to accept Jesus without denigrating Islam.
Festival organizers said they did not expect the more anti-Muslim group to return Saturday because they were scheduled to move on to a gay festival in Ohio.