WASHINGTON (CNN) -- Republican presidential candidate Rep. Tom Tancredo is standing by his new television ad depicting a terrorist attack on an American mall, saying it portrays a real threat.
In Rep. Tom Tancredo's ad, a hooded man leaves a backpack at a mall, and then an explosion is heard.
"Yes, they are coming, they are coming through our porous borders, and yes, they are coming to do us great damage," the Colorado Republican told CNN's Wolf Blitzer on Tuesday. "I don't know why anybody would not think this is true."
The 30-second ad, set to begin running on Iowa cable stations this week, depicts a hooded man walking into a crowded mall with a backpack. Over the sound of a ticking clock, the man abandons the backpack at a bench, and an explosion is heard.
"There are consequences to open borders beyond the 20 million aliens who have come to take our jobs," the ad's narrator says. "Islamic terrorists now freely roam U.S. soil. Jihadists, who froth with hate, here to do as they have in London, Spain and Russia." Watch Tancredo's ad »
Tancredo, who has placed the issue of illegal immigration front and center in his long-shot presidential bid, denied the ad was an attempt to bring attention to himself and raise his poll numbers.
"Never, ever did I expect to be a top-tier candidate, certainly at this point in time, never," he said. "I believe my candidacy has forced the issue of immigration to the top tier of debate topics. And now I am trying to force it to the next level."
Tancredo stands at 3 percent in the latest CNN/Opinion Research Corp. poll of national registered Republicans, and he registered 2 percent in a recent American Research Group poll of likely GOP Iowa caucus-goers.
On Monday, Bay Buchanan, Tancredo's campaign manager, brushed aside critics who say the ad is playing the "fear card." She cited a recent FBI memo that said officials had received a tip al Qaeda terrorists may be planning attacks on shopping malls in Los Angeles, California, and Chicago, Illinois, during the upcoming holiday season. The FBI has said there is no indication the tip is credible.
"That's a common response of individuals who don't like your message," Buchanan said of those who have said the ad is designed to instill fear. "But the key is this: Is there a concern that this could happen to us at anytime? It has to be the case; the FBI just confirmed it."
She added, "Washington doesn't have the guts, or the courage, or the will to do their job, which is to secure their nation, and that is why we face this threat. Unless we speak about it, we can't expect the American people to put the proper pressure on Washington to do what they were elected to do."
Tancredo caused a stir in August when he said bombing holy Muslim sites would serve as a good "deterrent" to prevent Islamic fundamentalists from attacking the United States.
Tancredo also turned heads in a May debate by invoking fictional "24" character Jack Bauer -- known for his hard-nosed, anti-terror techniques -- when asked if waterboarding would be appropriate in response to the detonation of nuclear devices on American soil.
"You say that nuclear devices have gone off in the United States, more are planned, and we're wondering about whether waterboarding would be a bad thing to do? I'm looking for Jack Bauer at that time, let me tell you."
Tancredo's ad isn't the first political commercial to portray an imminent attack on the United States. President Lyndon Johnson's infamous "Daisy" ad in 1964 pictured a young girl counting down to a mushroom cloud from a nuclear explosion. The ad ran once in Johnson's campaign against Sen. Barry Goldwater.
Over a loud explosion, Johnson is heard saying, "These are the stakes: To make a world in which all of God's children can live, or to go into the dark. We must either love each other, or we must die." E-mail to a friend