Florida Pastor Terry Jones had threatened to burn the Quran before, and in late March, he was present during the burning of a Quran by another pastor, Wayne Sapp. In apparent retaliation, Afghan protesters attacked United Nations workers and others over the weekend.

"For them to be assaulted and murdered by people purporting to be acting in the name of religion … that is the true outrage, and I hope people will resist any temptation even to equate the two," Frank said. "An act of stupid and offensive bigotry against a book should be criticized. No denigration of a religion could be greater than to murder innocent people in its name.

"If I were to be asked what did I think more detracted from the image of Islam, this irresponsible publicity seeker in Florida burning a Quran, or people in the name of the religion murdering innocent people, including those who went to Afghanistan only to help, it's clearly the latter," he concluded.