Latest Kenya anthrax test negative

NAIROBI, Kenya (CNN) -- Kenya's health minister says two letters sent to the United Nations in Nairobi that were suspected to contain anthrax have tested negative.

The announcement came a day after Kenyan health officials said preliminary tests on another letter sent to a Nairobi businessman had tested positive for anthrax.

Health Minister Sam Ongeri said on Friday that four other suspicious letters received in Kenya had been tested and found to be free of anthrax, but results were still awaited on a further two suspect letters.

The letter that tested positive was mailed on September 8 from the U.S. city of Atlanta via Miami and was received in Nairobi on October 9. It was opened on October 11.

VIDEO CNN's Catherine Bond reports on a package mailed from Atlanta to Nairobi, Kenya (October 18) Play video (QuickTime, Real or Windows Media)

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.