Anthrax has been found at another U.S. diplomatic mission overseas, this time in Russia. Officials at the U.S. consulate in the Siberian city of Yekaterinburg says a small amount of anthrax spores were found in a diplomatic mailbag sent from Washington last month.

It is the third time anthrax traces have been found at an American diplomatic post overseas.

Last week, the deadly bacteria was found in U.S. diplomatic mail arriving in Lithuania and Peru.

More than a month after the first case of anthrax poisoning surfaced in Florida, U.S. authorities are still trying to find out who is behind the spread of the disease that has killed four people.

In the United States, the FBI remains baffled about who is behind the anthrax attacks, including how anthrax may have killed a hospital worker in New York who had no obvious connection to the cases in Washington and Florida. Authorities are now looking into whether she may have crossed paths with whoever might have unleashed those attacks.

The U.S. Postal Service is now considering new ways of sanitizing the mail that would assure people that letters are being checked for anthrax before delivery. And chief postal inspector Ken Weaver says more postal inspectors are being put on duty around the country. "Inspection service personnel are posted at selected postal mail processing facilities around the country to screen mail," he explained.

No new cases of anthrax have been reported in more than a week.