Official Facebook page The White House defaced for a short time on Sunday, the tenth anniversary of the 9/11 terror attacks, with posts that appeared to be from Al-Qaeda, Taliban, or perhaps another terrorist organization.The posts came as authorities continue to exercise caution over what they called a"credible" threat against the United States, one that may involve attacks on infrastructure such as bridges or tunnels. The information provided by a source was scant, but indicated that three men would travel from Pakistan to the U.S. to carry out an attack.

The messages have been removed from the Facebook page, but one message, which featured an image of now dead 9/11 mastermind and Al-Qaeda leader Osama bin Laden, said, "We'll come back U.S.A. One day only 11/9/2011." Despite the format, the message refers to 9/11, using the day / month format used in other parts of the globe.

Another said, "We'll come to u white house sooooooooooon." A third said, "We'll come back 11/9/2011 to kill u all."

Secret Service spokesman Ed Donovan said that the agency had referred the messages to its Internet threat desk.