A new US report is to outline a handful of frightening scenarios for possible terrorist attacks on the country.
One of the scenarios outlined was an anthrax attack
The National Planning Scenarios report, drafted over the past year, covers hypothetical nerve gas, anthrax, truck bomb and pneumonic plague attacks.
A US spokesman said the plan would help officials to be more prepared to prevent and respond to acts of terror.
There is no credible information that any such attacks are being planned, according to officials.
The report, compiled by the Department of Homeland Security, is currently confidential but will be made public in the next few months, department spokesman Brian Roehrkasse told the Associated Press news agency.
"The overall goal is to increase the overall baseline preparedness of all states and and cities throughout the country," he said.
US President George W Bush requested the report 15 months ago after the Homeland Security Department was criticised by Congress for failing to focus funds on risk areas.
The department's new secretary, Michael Chertoff, said last week at his Senate hearing that he would make risk-based planning his central theme.
The New York Times published what it said were details of the report, posted mistakenly on a government website in the state of Hawaii.
It includes casualty figures and economic consequences for each of the possible scenarios.
According to the newspaper, these included:
- Blowing up a chlorine tank, killing 17,500 people and injuring more than 100,000
- Spreading pneumonic plague in the bathrooms of an airport, a sports arena and a railway station, killing 2,500 and making 8,000 ill worldwide
- Infecting cattle with foot-and-mouth disease, at a cost of hundreds of millions of dollars
- Spraying anthrax by aerosol from a truck passing through five cities over two weeks, exposing an estimated 350,000 people and killing about 13,200
- Setting off a "dirty bomb", causing 540 initial deaths but spreading over 36 blocks and contaminating local facilities, including transport systems and a sewage treatment plant.
Three natural disaster scenarios were included, the newspaper said:
- An influenza pandemic
- A 7.2 magnitude earthquake in a major city
- A slow-moving category 5 hurricane hitting a major east coast city.