The anthrax that killed two postal workers and forced the closure of mail rooms from the CIA to the Supreme Court was created in a sophisticated process that could have taken place in the United States or abroad, U.S. officials said on Friday. 
White House spokesman Ari Fleischer said investigators have determined that the pure, concentrated and highly dangerous anthrax delivered in a letter last week to Senate Majority Leader Tom Daschle "could be produced by a PhD microbiologist and a sophisticated laboratory." 
"That does not rule out that it could be state-sponsored," Fleischer said at a briefing. "That does not rule out that it could come from a foreign location. But it certainly does expand it beyond state sponsorship or foreign locations." 
There could be as many as 40 places in the United States with the ability to produce the lethal version of anthrax that was mailed to Senate Majority Leader Tom Daschle, according to Sen. Bob Graham, Senate intelligence committee chairman. 
"Most of them are associated with a university, a medical center or a veterinary center," Graham, a Florida Democrat, told Reuters. "But I don't believe any source of this has either been ruled in or ruled out, sources within the United States or elsewhere." 
In other developments, U.S. health officials weighed giving anthrax vaccines to investigators, new traces of the germ warfare agent were found at facilities that handle mail for the CIA, Supreme Court and other government locations, and U.S. postal officials elected to keep open a large mail-processing facility in New York where small amounts of the bacteria have been detected. 
CNN reported that U.S. health officials have decided to provide anthrax vaccines for criminal investigators and decontamination personnel, who are considered at high risk of exposure to the bacteria. The vaccine, its use currently restricted to certain laboratory workers and U.S. armed forces personnel, may be made available later to some U.S. postal workers, CNN added. 
Tests have found traces of anthrax in mail rooms that serve the CIA, the Supreme Court, Congress, the White House, the State Department and Walter Reed Army Institute of Research in suburban Maryland, as well as in the main mail distribution center for New York City. 
So far, three people -- two Washington postal workers and a photo editor at a Florida-based media company -- have died of anthrax in recent weeks. At least 11 people have become ill, including a State Department mail worker who was in stable condition at a Virginia hospital on Friday with inhalational anthrax. Thousands have been tested or treated for possible anthrax. 
President Bush inched closer to tying the anthrax attacks to Osama bin Laden, the Saudi-born fugitive Washington blames for the Sept. 11 hijack attacks that left some 5,000 people dead or missing. 
"We've seen the enemy in the murder of thousands of innocents, unsuspecting people ... The terrorists cannot be reasoned with," Bush said as he signed anti-terrorism legislation into law. "Witness the recent anthrax attacks through our postal service." 
A filter from the U.S. Supreme Court's off-site mail inspection warehouse several miles (km) away from the high court's building on Capitol Hill tested positive for the anthrax bacteria, court spokeswoman Kathy Arberg said. 
"We have no evidence of any contamination in the Supreme Court building," Arberg said. But authorities were testing the Supreme Court's 400 employees for possible exposure to the bacteria and giving them antibiotics as a precaution. 
The anthrax-tainted letter to Daschle was the only one so far confirmed to have come through the Washington area. Two others were sent to New York City: one to NBC News anchor Tom Brokaw and another to the New York Post newspaper. 
The New York postal facility through which those two letters may have traveled, the Morgan station near Madison Square Garden in midtown Manhattan, has tested positive for anthrax. Traces were found in four high-speed sorting machines. 
But U.S. postal authorities turned down union demands to close the facility. The Postal Service said the contaminated area was being cleaned and workers' health was not at risk. 
Postal workers have been offered the option of taking the antibiotic Cipro as a precaution. About 5,000 people work at Morgan station, just west of Madison Square Garden. William Smith, president of the 10,000-member New York Metro Area Postal Union, said employees "are taking their lives in their own hands" by working at the site. 
A "medically insignificant" trace of anthrax was discovered at the CIA's Material Inspection Facility (MIF), which handles incoming mail in Langley, Virginia, agency spokesman Bill Harlow said in a statement. 
No one at the CIA has shown signs of anthrax exposure, but the MIF was closed "in an abundance of caution," Harlow said. 
Two U.S. Army facilities in Maryland -- Walter Reed Army Institute of Research in Silver Spring and the U.S. Army Medical Research Institute of Infectious Diseases at Fort Detrick -- closed their mail rooms after anthrax was found at the Silver Spring site, just outside Washington. 
"We have a courier who carries mail between those two mail rooms three times a week, so to protect our own work force at Fort Detrick, we're looking at our mail room," Fort Detrick spokesman Charles Dasey said. 
Local officials in Washington also said they found anthrax traces in a postal facility in the southwest section of the nation's capital and expanded their testing for the bacteria to at least 2,000 smaller mailrooms around Washington. 
Officials said the postal service had begun environmental testing at 200 postal facilities along the East Coast and that random tests would be carried out at post offices nationwide as a precaution.