The FBI (search) warned police in California and New Mexico that it received information about possible terrorist activity in their states. However, the warning wasn't specific about particular targets or a method of attack, a federal law enforcement official said Thursday.

The FBI decided to pass along the threat information but warned that it was considered unsubstantiated and uncorroborated, said the official, who spoke only on condition of anonymity.

The vague warning was distributed to authorities in California, New Mexico and some other Western states the official did not identify.

U.S. officials earlier this month warned that a regular stream of intelligence indicates Al Qaeda (search ) wants to attack the United States to disrupt the upcoming elections.

Homeland Security Secretary Tom Ridge (search ) has said the government does not have specific knowledge about where, when or how an attack might take place.

Security was extremely tight at the Democratic National Convention (search ) in Boston this week. No terrorist-related activity has been reported.