The nation's anthrax scare worsened Friday as traces of the bacterium, which has killed three people, were found for the first time at CIA headquarters in Langley, Va., and at a mail-sorting facility for the U.S. Supreme Court.

Earlier, a State Department mail supervisor who works far from the center of anthrax infection was hospitalized with the inhaled form of the disease, a puzzle a top official called "the $64,000 question." A co-worker with flu symptoms was declared free from anthrax after overnight tests.

Trace amounts of the bacterium were also found in three congressional offices in the Longworth House office building on Capitol Hill, according to Capitol Police Lt. Dan Nichols. Anthrax was found in the offices of Reps. John Baldacci (D-ME), Rush Holt (D-NJ), and Mike Pence (R-IN).

The Longworth building, which has been closed since October 18, receives mail processed by a machine that had previously been found to be contaminated by anthrax. The machine itself is located in a different building.

"We are not concerned about a significant health risk, Capitol physician Dr. John Eisold said. The spores were found in trace amounts similar to those found in the Hart Senate Office Building earlier in the week, according to Nichols.

Eisold said that officials were trying to contact the lawmakers and other people who were in the building and that antibiotics would be made available to them.

From his home in Bangor, Maine, Baldacci said he was putting together a list of everyone who had been in his office, including visitors and interns. Baldacci also said the strain of anthrax found in his office was not as potent as that found in Senate Majority Leader Tom Daschle's office.

In Washington, presidential spokesman Ari Fleischer said officials had concluded that anthrax found last week in a letter addressed to Daschle "could be produced by a Ph.D. microbiologist in a sophisticated laboratory."

Fleischer said that finding indicates that the anthrax that has surfaced in Boca Raton, Fla., Washington, New York City and Trenton, N.J., "could be produced by a broader range of people" than foreign governments that sponsor terrorism.

He spoke one day after Sandra Carroll, a New Jersey-based FBI agent, said tests on the anthrax showed "it could be locally produced given the right circumstances. " Three tainted letters have turned up with postmarks from Trenton, N.J.

In remarks made as he signed anti-terrorism legislation into law, President Bush cited the recent "anthrax attacks through our postal service as evidence of an unprecedented war."

"We mourn the loss of lives," he said, referring to Washington postal workers Joseph P. Curseen Jr., 47, and Thomas L. Morris Jr., 55. The two men "died in the line of duty," he said.

A filter taken from the U.S. Supreme Court's off-site mail inspection warehouse tested positive for anthrax, the Court said in a statement Friday.

It said the filter was taken from the off-site facility Monday. It did not say where the warehouse was located.

"We have no evidence of any contamination in the Supreme Court building," the statement said. "Results of testing of our building completed by the Centers for Disease Control on Sunday were all negative."

Although no personnel showed any signs of exposure, the court was closed to the public as a precaution. It was still open for court employees.

The CIA's Material Inspection Facility, where the agency's mail is sorted, was closed after  the anthrax was discovered. Agency spokesman Bill Harlow called the detection "medically insignificant" and said it was the only one among 31 locations tested.

"It's not enough to cause inhalation anthrax," Harlow said. Even so, several agency employees who handle mail began taking antibiotics as a precaution.

Prior to testing at the Material Inspection Facility, CIA personnel and mail handlers were encouraged to get tested and take antibiotics because the mail receiving building receives its mail via Washington's central mail processing facility at Brentwood.

Until Thursday, all those infected in the nation's capital had been tied to Brentwood, which handles mail for federal agencies.

"It's conceivable that there's some incidental contact with mail that went through Brentwood," Harlow said.

The CIA has stepped up security at its mail center since the anthrax scare began, officials said. Harlow said the agency routinely checks its mail for suspicious substances and sometimes receives letters from deranged individuals.

The building where the anthrax was found is several hundred yards away from the two main CIA buildings. The CIA is unsure of how long the building will be closed due to the further testing and cleaning that will be done.

At the Pentagon, officials positioned truck-mounted biological detection stations that can detect a wide range of potential biological and chemical threats, including anthrax.

Thus far, officials have discovered only one piece of anthrax-tainted mail in the Washington area, the letter sent to Daschle's office. They are searching for more, though, since evidence of the bacteria has been confirmed in several places where that letter never traveled, including mail rooms serving the House, White House, the distant Virginia location that processes State Department mail and at the CIA.

Asked on CBS' The Early Show whether that meant other tainted letters were in circulation, Homeland Security Director Tom Ridge said, "That's the $64,000 question right now." He added: "It's really uncertain at this point."

The circle of infection widened with the diagnosis of the State Department mail supervisor, who worked more than 20 miles from Brentwood, Washington's central mail processing facility.

The 59-year-old man, hospitalized in guarded condition with inhaled anthrax, worked in Sterling, Va., where about 90 percent of the State Department's mail is processed, some of which comes from Brentwood.

Doctors asked him if his job ever took him to Brentwood. "His answer was 'never,"' reported Dr. Ivan Walks, Washington's chief health officer.

The State Department's mail facility was being tested for anthrax exposure Friday, as were 250 to 300 workers, with about 80 of them immediately given preventive antibiotics. Another half dozen State Department locations also were to be tested, including two inside the Foggy Bottom headquarters.

Also, a test for anthrax in a mailroom in the Walter Reed Army Institute of Research in Silver Spring, Md., came back positive Thursday. The institute, which doesn't care for patients, is three miles from the hospital at the Walter Reed Army Medical Center.

Trying to get ahead of the spiraling threat, the Postal Service began anthrax testing at hundreds of facilities along the East Coast and at every government mailroom, and did spot checks nationwide. Washington health officials asked virtually everyone involved with mail handling to report for antibiotics, and thousands of New York postal workers were prescribed the drugs too, even though further evidence of anthrax has not been found there.

Attempting to reassure anxious customers, the Postal Service was purchasing new irradiation equipment to kill any germs in the mail in selected areas. The equipment, similar to that used in food processing, uses electron beams and X-rays to kill bacteria.

The number of confirmed infections reached 13, all linked to the media or the mail. All of the infections occurred in Florida, New York, New Jersey or metropolitan Washington.

Among those with inhalation anthrax, three had died, three were hospitalized and one had recovered. Another six people have been diagnosed with the highly treatable skin form of the disease.

The Associated Press contributed to this report.