(AP) - An Afghan immigrant who received explosivestraining from al-Qaida went from one beauty supply store toanother, buying up large quantities of hydrogen peroxide andnail-polish remover, in a chilling plot to build bombs for attackson U.S. soil, authorities charged Thursday.

Najibullah Zazi, a 24-year-old shuttle driver at the Denverairport, was indicted in New York on charges of conspiracy to useweapons of mass destruction. Investigators found bomb-makinginstructions on his computer's hard drive and said Zazi used ahotel room in Colorado to try to cook up explosives a few weeks agobefore a trip to New York.

Over the past few days, talk of the possible plot set off themost intense flurry of national terrorism warnings in the U.S.since shortly after the Sept. 11, 2001, attacks in New York andWashington.

Prosecutors said they have yet to establish exactly when andwhere the Zazi attacks were supposed to take place. But AttorneyGeneral Eric Holder said in Washington, "We believe any imminentthreat arising from this case has been disrupted."

A law enforcement official told The Associated Press on Thursdaythat Zazi had associates in New York who were in on the plot.

Zazi was arrested in Denver last weekend and was charged alongwith his father and a New York City imam with lying toinvestigators. Authorities said in the past few days that theyfeared Zazi and others might have been planning to detonatehomemade bombs on New York trains, and warnings went out to transitsystems, stadiums and hotels nationwide.