BROOKLYN - (AP) - An Afghan immigrant has pleaded not guilty to plotting a terrorist attack on New York City using common chemicals.

Najibullah Zazi's lawyer entered the plea Tuesday in Brooklyn. Zazi was ordered held without bail during the brief hearing.

Defense attorney J. Michael Downing says what he's seen so far "does not amount to a conspiracy."

A law enforcement official confirmed Monday that investigatorshad identified three people believed to have been in on the scheme.The official spoke on condition of anonymity because theinvestigation continues. The accomplices are suspected of traveling from New York City tosuburban Denver this summer and using stolen credit cards to helpZazi stockpile bomb ingredients, authorities have said. "I don't know the names of anybody else that allegedlyconspired with Mr. Zazi," Dowling said Tuesday. "Those names havenot been produced." Before authorities made a series of raids in the case, policedetectives showed a source - a Queens imam at a mosque where Zazihad once worshipped - photographs of him and three peopleconsidered possible suspects, court papers say. It was unclearwhether those three were the same ones suspected of traveling toDenver. There have been no reports that the bomb-making materials havebeen recovered. Prosecutors allege that Zazi has admitted that while living inQueens, he traveled last year to Pakistan and received explosivestraining from al-Qaida. Security videos and store receipts showthat when he returned and moved to Aurora, Colo., he and threeothers bought several bottles of beauty products over the course ofseveral weeks, court papers said. On Sept. 6, Zazi took some of his products into a Colorado hotelroom outfitted with a stove on which he later left acetone residue,authorities said. He repeatedly sought another person's helpcooking up the bomb, "each communication more urgent in tone thanthe last," the papers said. The FBI was listening to Zazi and becoming increasinglyconcerned as the anniversary of the Sept. 11, 2001, attacks and aNew York visit by President Barack Obama approached, officialssaid. They decided to track him on Sept. 9 when he rented a car anddrove to New York. On Sept. 10, Zazi told the Queens imam in an intercepted phonecall that he feared he was being watched, court papers said. Theimam later tipped Zazi off, saying police had come around and askedquestions, the papers said. Zazi cut short a five-day trip and flew back to Denver on Sept.12. He was arrested a week later and initially charged along withhis father and the imam with lying to investigators. A letter filed by Brooklyn prosecutors last week argued thatZazi should be jailed indefinitely because, as an immigrant withties to Pakistan, he could flee, and because he "poses asignificant danger" to the community. Evidence gathered - including bomb-making instructions found onhis laptop computer - shows "Zazi remained committed to detonatingan explosive device" until he was arrested, the letter said. Zazi's next court date has been set for Dec. 3.