Two US postal workers who died in "suspicious" circumstances were "likely" to have been infected with anthrax, the Homeland Security chief, Mr Tom Ridge said yesterday.
Blood tests taken from the men, who had suffered from pneumonia-like symptoms and respiratory problems, have produced "suspicious preliminary test results". One of the men died only hours after he arrived in hospital yesterday morning.
The US Surgeon General, Dr David Satcher, also confirmed the deaths of the two postmen were likely to be from anthrax. "It does seem highly probable that those two deaths were related to inhalation anthrax." He said it was urgent that anyone who had been working in the area or had symptoms should go to hospital. "We don't have a lot of time with inhalation anthrax," he said.
This would bring the number of deaths from anthrax in the US in the past few weeks to three.
The men worked at a "back postal area" in Washington's main sorting office where investigators believe three letters containing anthrax were sorted. Two other postmen working at the facility have tested positive for pulmonary anthrax - a more dangerous form of the disease than the cutaneous (skin) version that has affected postroom workers in New York.
The condition of one man, 57-year-old Mr Leroy Richmond, has deteriorated and is now described as serious. A further nine people in the Washington area are suffering from anthrax-like symptoms and are anxiously awaiting test results.
The news prompted criticism of the centre for disease control and prevention (CDC), which had advised that no one working in the Brentwood mail office needed to be tested for anthrax at the end of last week. It also raised the alarming possibility that there might be another highly potent anthrax letter in wider circulation that may have passed through the Brentwood office and has yet to be detected.
Investigators are attempting to discover whether the workers handled the same letter that contained finely milled anthrax which was sent to the Senate majority leader Mr Tom Daschle and caused a week of turmoil on Capitol Hill, or other letters sent to the New York Post and NBC television's news anchor, Mr Tom Brokaw. More than 2,000 workers at the Brentwood facility are now being tested.
Mr Ivan Walks, Washington's chief health officer, said authorities are investigating nine more cases that have aroused concern and he did not know how many of those nine were postal workers or how many were in hospital.
Swabs have been taken from the sorting office and the mail processing equipment which the Daschle letter passed through but the results will not be known for a few days. Two sorting offices - the Brentwood office and an airmail facility near Baltimore Washington international airport - have been closed.
The Capitol building - which had been closed after the discovery of the anthrax letter to Senator Daschle - reopened but nearby congressional offices remained shut for environmental testing. Congressional sources said it was unlikely that all the House and Senate office buildings would reopen tomorrow as officials had hoped.
Testing was continuing but it was not clear whether all the results would be in hand by this morning.
Officials discovered anthrax over the weekend in a building where mail for offices at the House of Representatives is processed.
There have been no test results yet indicating anthrax in any of the other House office buildings, again leaving authorities wondering if an as yet undiscovered piece of mail was the source of spores found on a postroom machine there.