Two campaign offices for Republican White House hopeful John McCain were evacuated and staffers quarantined after threatening letters containing suspicious powder were received, officials said.
The first letter arrived at the Republican's campaign headquarters in a suburb of Denver, Colorado. A second letter was later reported at a McCain office in Manchester, New Hampshire.
Staff members were sent to medical facilities for treatment under quarantine while FBI and Secret Service agents joined hazardous materials experts at both scenes.
Secret Service spokesman Eric Zahren told AFP that the first envelope received in Centennial, a Denver suburb in the western state, "also contained a generic warning regarding the contents," but gave no further details.
"McCain staffers reported that they had received an envelope containing white powder in McCain's campaign office in Centennial," Zahren said.
