http://www.fbi.gov/pressrel/pressrel01/101101.htm

For Immediate Release October 11, 2001	Washington D.C. FBI National Press Office
Certain information, while not specific as to target, gives the government reason to believe that there may be additional terrorist attacks within the United States and against U.S. interests overseas over the next several days. The FBI has again alerted all local law enforcement to be on the highest alert and we call on all people to immediately notify the FBI and local law enforcement of any unusual or suspicious activity. ####

-- Anonymous, October 11, 2001

Answers

http://www.msnbc.com/news/639359.asp

FBI: Attacks possible within days
Bureau issues second warning in five days
Sportswriter Renee Harris undergoes a thorough security check Wednesday at Yankee Stadium before the first game of the American League playoff game between the New York Yankees and the Oakland A's.
NBC, MSNBC AND NEWS SERVICES

WASHINGTON, Oct. 11 —  Saying it has received information that new terrorist attacks may be planned inside the United States or abroad in the next several days, the FBI on Thursday asked local police to be on the highest alert and urged all Americans to be wary of suspicious activity

-- Anonymous, October 11, 2001