WASHINGTON (CNN) -- Why did terrorists attack the U.S. on 9/11?

According to Texas Congressman Ron Paul, "They attack us because we've been over there. We've been bombing Iraq for 10 years. We've been in the Middle East."

Restrained, but clearly angry, former New York City Mayor Rudy Giuliani jumped in, calling Paul's statement "extraordinary."

"As someone who lived through the attack of September 11 -- that we invited the attack because we were attacking Iraq -- I don't think I've ever heard that before, and I've heard some pretty absurd explanations for September 11th," he said.

Giuliani's fiery response prompted applause and the following demand from the former mayor: "I would ask the congressman to withdraw that comment and tell us that he didn't really mean that."

In response, Paul stood by his comments and said that "if we think that we can do what we want around the world and not incite hatred, then we have a problem ... They come and they attack us because we're over there."

-- CNN Senior Producer Alex Wellen