White powder in a letter mailed from Atlanta to a Kenyan has tested positive for anthrax spores, the health minister said Thursday, the first case of a tainted letter outside the United States since the Sept. 11 attacks. 

Health Minister Sam Ongeri told a news conference that the unidentified recipient and four family members ``may have come into contact'' with the spores and were being tested, but they are ``not in danger.'' The powder was undergoing further tests, he said.

White powder was found in two other letters — one to an official with the U.N. Environment Program in Nairobi and the other to a Kenyan businessman in the central town of Nyeri, Ongeri said. Those letters were being tested at the state-run Kenya Medical Research Institute, he said.

The letter that tested positive for anthrax had been mailed Sept. 8 from Atlanta, Ongeri said, and was received in Kenya on Oct. 9. It was opened on Oct. 11.

The hand-addressed letter to the U.N. official was mailed from Pakistan, and the letter to the businessman appeared to have been mailed from Nairobi, he said.

UNEP spokesman Nick Nuttall said the letter from Pakistan had seemed suspicious.

``It was a very sort of dirty looking envelope with rather eccentric writing on it. It just looked dirty, odd and suspicious. We get thousands of letters and some do look a bit odd,'' Nuttall said.

Anthrax is not contagious and can be treated with antibiotics. It is endemic in this East African nation, infecting people who come in contact with contaminated meat or hides, Ongeri said.

In the United States, four people are known to have contracted the disease and nine others have tested positive for the bacteria since the attacks on the World Trade Center and the Pentagon.

The anthrax scares have caused jitters worldwide. There have been scares and hoaxes, but so far, no one outside the United States has tested positive for the bacteria. Yet hundreds of pranks or suspicious incidents have generated widespread public fear.

Authorities in Kuala Lumpur insisted Thursday that an anthrax-tainted letter sent to a Microsoft office in Nevada was not contaminated in Malaysia, though it appeared to have been mailed from this Southeast Asian country. Six people exposed to the letter tested negative.

In Beijing, government health workers disinfected people who came into contact with suspicious substances enclosed in a letter sent to an American firm, China's Foreign Ministry said Thursday. The substance was being tested. The letter contained information about the banned Falun Gong spiritual movement.

A car bomb exploded outside the U.S. Embassy in Nairobi in 1998, almost at the same time as another explosion at the U.S. Embassy in Tanzania. Twelve Americans and more than 200 Kenyans were killed in the Aug. 7, 1998, blast. International terrorist suspect Usama bin Laden has been indicted for masterminding the embassy bombing.