DENVER A suburban Denver campaign office of U.S. presidential candidate John McCain was evacuated on Thursday, and several people went to a hospital, after receiving an envelope containing a threatening letter and an unidentified white powder, a campaign spokesman said.
The letter arrived in the mail in the afternoon, and the campaign immediately notified local and federal law enforcement authorities, said Jeff Sadosky, a spokesman for the campaign in suburban Washington, D.C.
McCain, 71, a Republican senator from Arizona, was taking the day off from the campaign, spending the day at his home in Sedona, Arizona.
Sadosky added, "We are taking all necessary precautions," which he said included an evacuation of the office in Centennial, Colorado, outside Denver, where dozens of people work.
He said the composition of the powder found in the envelope was not immediately known, and that he did not know to whom the parcel was addressed.
Five to 10 people who were in the office went to a nearby hospital, where "they are currently being seen by health-care professionals," Sadosky said.
Five people died in 2001 after anthrax powder was mailed to U.S. congressional offices and media outlets in the weeks following the September 11 attacks.
A U.S. Secret Service spokesman, Malcolm Wiley, said the envelope sent to the McCain campaign office was opened by a campaign staffer there, and that an FBI hazardous materials team was dispatched to the scene, along with Secret Service personnel and local authorities.
A police spokeswoman in Denver said she had no immediate information about the incident.
The Democratic National Convention is due to open in Denver on Monday.
(Reporting by Steve Gorman, Dan Whitcomb and Jill Serjeant; editing by Eric Beech)