NEW YORK -- New York City police are investigating suspicious white powder found in envelopes at American Express Co. headquarters, near the site of the Sept. 11 attacks.

Detective Mindy Diaz says no injuries were reported after police were called to the building in lower Manhattan on Thursday afternoon.

Diaz says three people were exposed to the powder, which authorities were testing. Detective Cheryl Crispin says the three have been decontaminated.

American Express spokeswoman Joanna G. Lambert says business has not been interrupted.

In October and November 2001, five people were killed after coming in contact with mailings containing anthrax.

In November, at least four U.N. foreign missions received packages containing suspicious powder.

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