U.S. Attorney General John Ashcroft says there is credible evidence of a new terrorist threat. The U.S. government is moving to a higher alert status as a result.

Attorney General Ashcroft said Monday the evidence does not specify how or where an attack might take place, but that 18,000 law enforcement agencies have been put on high alert.

"The administration has concluded that, based on information developed, that there may be addition terrorist attacks within the United States and against U.S. interests over the next week," Mr. Ashcroft said. "The administration views this information as credible, but unfortunately it does not contain specific information as to the type of attack or specific targets."

Mr. Ashcroft said all federal agencies have been advised. Attorney General says the administration decided to inform the public as a precautionary measure.

The head of the Federal Bureau of Investigation, Robert Mueller, said 18,000 law enforcement agencies have been put on alert too. He said, "I believe it is advisable to alert law enforcement and local authorities as to what knowledge we have received. We are again asking them and through them and local communities to remain extremely vigilant. Doing so gives us a force multiplier that could well prevent another terrorist attack."

This is the second terror alert in as many weeks. Mr. Mueller says increased security following the warning issued on October 11 may have helped avert an attack although he acknowledged it is difficult to say for sure. Mr. Mueller refuses to speculate about any links between the terror alerts and the discovery of more anthrax cases at post offices servicing government agencies.