DENVER -- A 24-year-old Colorado man denied Tuesday that he's a central figure in a terrorism investigation that fed fears of a possible bomb plot and led to several police raids in New York City.

"Of course not," said Najibullah Zazi. "I have nothing to do with al-Qaida, any link or anything with al-Qaida"

Two law enforcement officials confirmed Tuesday that a joint FBI-New York Police Department task force had put Zazi under surveillance because of suspected links to al-Qaida. But the FBI in Denver said it couldn't comment, and Zazi insisted he's not under investigation.

Zazi told the Associated Press he recently visited New York City -- and was subject to what he described as a routine traffic stop Sept. 10 on the George Washington Bridge, which connects New York City and New Jersey. But he said he was allowed to leave and return to Denver.

"All I can say is that I have no idea what it is all about," Zazi said. "I spent two days in New York, flew back, and I have nothing else to say ... I am an airport driver and that's all I can say."

Zazi's attorney Art Folsom told 7NEWS "There is no investigation going on and at this point in time we have nothing further to say other than that my client is completely innocent. If anything this is a matter of guilt by association."

Law enforcement officials told ABC News that Zazi had recently traveled to Pakistan before he showed up in New York last Thursday with bomb-making documents.

The New York task force also feared Zazi may be involved in a potential plot involving homemade hydrogen peroxide-based explosives like those cited in an intelligence warning issued Monday, said the officials, who were not authorized to speak about the investigation and insisted on anonymity.

Folsom denied the allegations saying "If the feds are that interested in him, why is it they haven't served a search warrant? Why is it they haven't shown up to ask him any questions? Why is it they haven't made any attempt to do anything as far as we can tell?"

Elected officials from New York said the FBI and New York Police Department, after tailing Zazi, raided three homes early Monday in New York searching for explosives, bomb-making materials and possible al-Qaida operatives. Investigators searched three apartments and questioned residents, including an Afghan immigrant who knew Zazi, but there were no arrests.

The surprise raid rattled an urban, predominantly Asian neighborhood in a remote part of Queens.

Colorado officials stressed there is no threat to the state or the country.

U.S. Sen. Mark Udall told 7NEWS he spoke with the FBI and Department of Homeland Security about the case.

"They said there is no imminent threat. They didn't expand on it, they didn't explain the context," he said.

Kathleen Wright, a special agent with the FBI in Denver, declined comment except to say, "I cannot confirm or deny any of the media reporting."

Gov. Bill Ritter's office said he had been briefed on the investigation regularly over the past several days by law enforcement agencies involved in the Joint Terrorism Task Force. CALL7 Investigators have learned that the governor's office of Homeland Security had been involved in the investigation and they believe there is no imminent threat in Colorado.

The investigation is ongoing. A law enforcement source told CALL7 Investigators that the investigation has been going on for two weeks.

Zazi's aunt, Rabia Zazi, 35, told the AP that Najibullah was born in Pakistan and moved to the United States at an early age. He grew up in New York City and recently moved to Colorado, where he helps his father with an airport shuttle business, she said. Asked if there was any reason to suspect him of any kind of illegal activity, she insisted: "He doesn't have time. He's working."

Throughout the day there had been reports that the massive FBI probe that triggered raids in New York City is focused on a potential Denver-based terror cell plotting another attack on the scale of 9/11.

Hundreds of FBI agents are "on the ground in Colorado, conducting round-the-clock surveillance on five suspects," the New York Daily News reported.

FBI spokesman James Margolin confirmed that authorities executed search warrants at multiple locations in connection with what he called an "ongoing investigation." He would not elaborate.

The execution of search warrants came after days of surveillance.

Bomb-making materials were not found during the New York City raids, according to ABC and additional searches were under way in Colorado.

The FBI and Homeland Security officials warned local law enforcement agencies to be on the lookout for materials that could be used to make explosives, 7NEWS learned.

The joint FBI and Homeland Security intelligence warning lists indicators that could tip off law enforcement to homemade hydrogen peroxide-based explosives, such as people with burn marks on their hands, face or arms; foul odors coming from a room or building; and large industrial fans or multiple window fans.

The warning also said that these homemade explosive materials can be hidden in backpacks, suitcases or plastic containers.

"The FBI is seriously spooked about these guys planning another 9/11," a former senior counter terrorism official told the Daily News. "This is not some ... FBI informant-driven case. This is the real thing."

A friend told ABC News that federal authorities targeted the wrong man.

"He's not dangerous. He's a kid, so he can't be dangerous," the friend told ABC News.

A White House spokesman said the president "has been kept fully apprised of developments" but referred all further questions to the FBI.

The Washington Post reported that high-level federal officials delivered classified briefings Monday on Capitol Hill. Sources familiar with the Washington briefings said it was unclear how close the plot was to acquiring weapons or selecting a target, but several unspecified factors, including uncertainty over the scope of the threat, prompted the raids.