Fiery Republican presidential long-shot Tom Tancredo has defended his suggestion that America should threaten to bomb Muslim holy sites in order to deter a nuclear attack on US soil.

Mr Tancredo first mooted his controversial position last week, prompting the State Department to describe it as "absolutely crazy."

"Yes, the State Department -- boy, when they start complaining about things I say, I feel a lot better about the things I say," the Colorado representative said in a presidential debate in Iowa televised on American ABC.

"My task as president of the United States is primarily to do one thing - by the way, not to make sure everybody has health care or everybody's child is educated - my task is to do one thing: to protect and defend this country.

"And that means to deter - and I want to underline 'deter' - any kind of aggression, especially the type we are threatened with by Al Qaeda, which is nuclear attack.

"I'm telling you right now that anybody that would suggest that we should take anything like this off the table in order to deter that kind of event in the United States isn't fit to be president of the United States."

The State Department on Friday reacted angrily to Tancredo's initial comments.

"Let me just say that it is absolutely outrageous and reprehensible for anyone to suggest attacks on holy sites - whether they are Muslim, Christian, Jewish or those of any other religion," departmental spokesman Tom Casey said.

Tancredo was quoted by the Iowapolitics.com website last week as saying the best way he could think of to deter a nuclear terrorist attack on the United States was to threaten to retaliate by bombing Islamic holy sites.

-AFP