Suspicious powder found at State Department

WASHINGTON (CNN) -- FBI counterterrorism agents arrived at the State Department Wednesday after a suspicious powdery substance was found in the mailroom.

Lynn Cassel, a department spokeperson, told reporters a white powder was found on the floor of the sixth floor mailroom, prompting calls to the FBI and the District of Colombia's hazardous materials division.

The building was not evacuated, but the State Department did shut off its air conditioning system. Several ambulances and firetrucks also responded, Cassel said.

"We have no idea where the substance came from," she said.

As investigators scrambled to learn more about the substance, a female employee who found the powder was examined by paramedics. "She is fine," Cassel said.

Paramedics said they examined another man who "felt ill." The paramedics said the man was "under quarantine" and they cautioned reporters not to touch him.

One paramedic said that more than one but fewer than five other people were under quarantine.

State Department spokesman Richard Boucher said Wednesday that all U.S. embassies and consulates around the world were asked to stock a three-day supply of antibiotics to treat a chemical or biological attack.

He said for the past few years select posts have been sent chemical antidotes and antibiotics as a "a precautionary measure."

Boucher said the United States did not have "any information to indicate that there's an imminent threat from the use of anthrax or other biological agents at an overseas mission."