Protesters gathered across the street from Phoenix's largest mosque on Friday, shouting obscenities and holding up signs depicting the Islamic prophet Muhammad, but a line of police kept the crowd from mixing with those attending evening prayer.
The protest was held at the mosque once attended by two men who attacked a Muhammad cartoon contest held this month in Garland, Texas. Both attackers were killed by police.
Organizers said the gathering was to demonstrate against Islam and the violence perpetrated by radical militants over depictions of Muhammad.
Organizer Jon Ritzheimer, wearing a black T-shirt with an obscene message denouncing Islam, said he had to go into hiding because the Islamic State militant group publicized his address.
The protesters had planned a post-rally meal at the nearby Wild Bill's Saloon, but the restaurant closed its doors, posting a note saying that it respects the community and would reopen Saturday.
The mosque leadership urged attendees not to respond to taunts from the protesters.
"You can't judge a whole mosque for two guys," said Talal Yousufzai, who, despite the mosque's warning, engaged in a prolonged shouting match with the protesters across the street.
Counter-protesters behind him shouted: "U-S-A, U-S-A!"