Fears were today mounting that the danger to the public from America’s anthrax outbreak was greater than had initially been believed.

More than 2,000 postal workers were tonight awaiting the results of anthrax tests after a colleague in Washington DC was diagnosed with the most serious form of the infection.

FBI detectives believe they have found the anthrax-laced letter which infected a worker at the New York Post newspaper, it was revealed today.

US officials are today trying to calm mounting anthrax fears after two more cases of the desease were confirmed.

A New York Post employee has contracted skin anthrax, a television station affiliated with the newspaper reported today.