US offers $1m reward over anthrax mailings

The US government offered a $1m reward yesterday for information about those behind the spate of anthrax mailings as it was revealed that an assistant to America's best-known television anchorman has also been infected with the bacteria.

The CBS news presenter Dan Rather said a female member of staff had been infected with the cutaneous form of the disease. She was being treated with antibiotics and was expected to make a full recovery.

Meanwhile, in the first case outside the US, the authorities in Kenya said at least four people had been exposed to spores contained in a letter posted from Atlanta. The announcement, by the Health Minister, Sam Ongeri, appears to indicate that the East African country has a central role in Osama bin Laden's international network.

The FBI director, Robert Mueller, said the $1m reward was being offered jointly by the bureau and the Postal Service. "Once again we call upon the public to assist us in this fight against terrorism," he said.

The Attorney General, John Ashcroft, said he would prosecute to the "fullest extent of the law" anyone creating hoaxes involving anthrax or other bio-chemical threats. Four people have already been charged, among them a Florida teenager, James Smith, who disrupted a lesson by leaving a white powder on his teacher's desk.

A total of six people have now been infected. One, a British-born picture editor, Bob Stevens, died after a letter was posted to the Florida newspaper at which he worked.

A postal worker who may have handled letters containing anthrax that were sent to the US Senate in Washington and NBC in New York has tested positive for exposure to the spores. A total of 31 people at the Senate tested positive after a letter was sent to the Majority leader, Tom Daschle, while an assistant to the television news presenter Tom Brokaw is being treated after opening a package.

The Kenya letter – which contained pieces of cloth and white powder – was posted to a businessman in the capital, Nairobi, on 8 September. Mr Ongeri said the letter was received in Kenya on 9 October and opened on 11 October.

He did not specify which strain of anthrax was involved, and declined to name the family exposed, but said they were "not in danger".

Mr Ongeri said that two further letters were being tested. One was delivered on Wednesday to a United Nations office in Nairobi. A health ministry official said it had a Pakistani stamp. The thirdwas received in the Kenyan town of Nyeri, and had been sent from Nairobi.

The announcement coincided with the sentencing in New York of two suspects in the 1998 US embassy bombings in Nairobi and Dar es Salaam. Inquiries by The Independent indicate that, despite US pressure since 1998, Kenya has remained a key location for Mr bin Laden's activities.

Of the 22 African nationals on the US Treasury's list of terror suspects, four have Kenyan passports or dual citizenship. River Road, in central Nairobi, and the suburb of Eastleigh, are centres for forgers making school records, birth certificates and university qualifications, with which it is possible to apply for a legitimate Kenyan passport.

It is unclear why Kenya may have become the target of an anthrax campaign. Its government has backed the US attacks on Afghanistan, but so have many others in the region.