The Secret Service is investigating threatening messages that were left on the White House Facebook page, amid heightened alerts surrounding a possible Sept. 11 terror threat.
The messages included a picture of Osama bin Laden. One said, "We'll come back U.S.A. One day only 11/9/2011," using the date/month formula to reference Sept. 11.
"We'll come to u white house sooooooooooon," another said.
Another showed small plane icons and said, "We'll come back 11/9/2011 to kill u all."
The posts appeared briefly and were taken down.
Secret Service spokesman Ed Donovan said the agency referred the messages to its Internet threat desk.
WNBC in New York was the first to report on the messages.