WASHINGTON -- A Republican presidential hopeful said during a campaign stop in Iowa that the best way he can think of to deter a nuclear terrorist attack on the U.S. is to threaten to retaliate by bombing Islamic holy sites.

Attack Mecca? | Compare Candidates

Colorado Rep. Tancredo, R-Colo., The Colorado congressman on Tuesday told about 30 people at a town hall meeting in Osceola, Iowa, that he believes such a terrorist attack could be imminent and that the U.S. needs to hurry up and think of a way to stop it.

"If it is up to me, we are going to explain that an attack on this homeland of that nature would be followed by an attack on the holy sites in Mecca and Medina," Tancredo said at the Family Table restaurant. "Because that's the only thing I can think of that might deter somebody from doing what they otherwise might do."

Mecca and Medina, in Saudi Arabia, are Islam's holiest cities. All able-bodied Muslims are required to make a pilgrimage there at least once in their lives. Tancredo's comments were recorded and posted on the Web site iowapolitics.com.

By Friday, his comments had reached parts of the Muslim world. In Lahore, Pakistan, at least one U.S. flag was burned during street demonstrations against Tancredo.

A Washington-based Islamic civil rights and advocacy group responded in anger Thursday, calling Tancredo's statement "unworthy of anyone seeking public office in the United States."

"Perhaps it's evidence of a long-shot candidate grasping at straws and trying to create some kind of a controversy that might appeal to a niche audience of anti-Muslim bigots," said Ibrahim Hooper, spokesman for the Council on American-Islamic Relations.

Campaign spokesman, Alan Moore, said Tancredo stands by his statement.

This isn't the first time Tancredo has suggested taking extreme action against Mecca and Medina.

In 2005, he drew international criticism after he told a radio talk show host that "you could take out" Islamic holy sites if terrorists ever launched a nuclear attack against the United States.