Three new cases of exposure to anthrax have been uncovered in New York, Mayor Rudy Giuliani said today, stressing the individuals had not developed the disease.
That brings to eleven the total number of people exposed to anthrax in the US to date, one of whom has died.
Mr Giuliani said a police officer and two laboratory technicians involved in handling a letter sent to NBC, which infected a member of staff at the television network, had tested positive for spores of anthrax.
"When they were tested miniscule spores or a spore were found, in two cases in their nose and in one case on their face," Giuliani said.
"They are being treated. This does not mean, and I emphasise, that they have anthrax," he said.
Meanwhile the US Health and Human Services Secretary Mr Tommy Thompson has described the spate of anthrax-contaminated mail in the United States as bio-terrorism but said it was too early to blame Osama bin Laden's al Qaeda network.
"There's no question it's bioterrorism", Mr Thompson said on CNN’s Late Edition programme.
"It's a biological agent. It's terrorism, it's a crime... But whether or not it's connected to al Qaeda, we can't say conclusively", he said.
Earlier Mr Thompson said the people behind anthrax-tainted letters received in New York and Nevada could be Americans.
"It could be a domestic source. It could be somebody holding a grudge. It could be ... a copycat kind of a situation", he said.
Mr Thomson sought to calm public jitters over the mailings and over an outbreak of anthrax in a Boca Raton, Florida building housing supermarket tabloids in which one man died and at least seven others were exposed to the bacteria.
The health secretary said that despite a lot of "false rumors", there was no conclusive evidence that germ warfare had been launched on America by the al Qaeda network, now under attack by bombs and missiles in its bases in Afghanistan.
AFP