Anthrax spores mailed to Kenya

NAIROBI, Kenya (CNN) -- Kenya's health minister says an envelope sent from Atlanta to a private Kenyan citizen has tested positive for anthrax spores.

Authorities are investigating two other envelopes containing white powder, including one sent to a U.N. office in Nairobi.

Sam Ongeri, the health minister, said the letter that tested positive was mailed September 8 from Atlanta via Miami and was received in Nairobi on October 9. It was opened on October 11.

The letter contained white powder and pieces of cloth. The person who received it took it to the health ministry and it tested positive.

The citizen's name was not revealed. Four direct members of the person's family were under observation. News reports in Kenya say the man is a doctor, but that could not be independently confirmed.

Another letter with whitish powder was sent from Nairobi to a businessman in Nyeri. It was brought to the health ministry's attention on Wednesday.

A third envelope with powder was sent to the U.N. Environmental Programme. It had Pakistani stamps on it, but the postmark was not disclosed.

CNN's Nairobi Bureau Chief Catherine Bond said that the envelope was being described as "grubby with writing all over it."

U.N. officials said that where the stamp normally be the word "immaculate" was written in English. Pakistani stamps were on the back of the envelope, which was described as brownish-gray in colour and tattered.

The address was described as being written in clumsy handwriting.

U.N. officials said the unopened envelope was handed to security officials by employees of the media office who thought it was suspicious. Kenya's Medical Research Institute in Nairobi was testing the envelopes.

Bond says the Kenyan authorities have been stocking up on antibiotics including penicillin and have obtained emergency stocks of plastic gloves for anyone coming into contact with the disease.

Meanwhile, three men convicted of having a hands-on role in the suicide truck bombings of the American embassies in Nairobi, Kenya, and in Dar es Salaam, Tanzania, on August 7, 1998, are to be sentenced on Thursday.

Also to be sentenced is a fourth man who was a longtime aide to suspected terrorist Osama bin Laden.

The nearly simultaneous embassy attacks killed 224 people, including 12 Americans, and injured another 4,500 people.

The men were convicted in the only U.S. trial to date against followers of bin Laden. They will be sentenced on Thursday in the same Manhattan federal courtroom where a jury found them guilty in May.