Threatening messages were posted on the White House Facebook Page on 9/11's anniversary. At least three posts referencing the events of September 11, 2001, appeared briefly before they were taken down, according to NBC News:
We'll come back U.S.A. One day only 11/9/2011. We'll come to u white house sooooooooooon. We'll come back 11/9/2011 to kill u all.
Secret Service spokesman Ed Donovan said the agency has referred the messages to its Internet threat desk, which has a specific process in place to handle the wide spectrum of social media posts brought to the attention of officials, according to CBS News.
The posts come amid heightened alerts surrounding a possible 9/11 terror threat, which has been described as "specific" and "credible" but not confirmed. New York City and Washington DC have tightened security after intelligence collected from overseas indicated a possible threat involving car bombs, as well threats to bridges and tunnels. The information indicated that three men would travel from Pakistan to the US to carry out an attack but so far precautionary interviews with travelers have drawn a blank.
The scrutiny of airline passenger records has turned up well over 100 names of interest, all of whom have been interviewed but were not found to be part of any terror plot. Some were, however, added to terror databases simply because of their travel patterns. Additionally, the FBI has found no sign of unusual purchases of chemicals needed to make car bombs around the New York and Washington areas.
A joint FBI-Department of Homeland Security bulletin from Thursday said al-Qaida may be considering attacks that use improvised explosives packed in vehicles. The goal would be to avenge the death of Osama bin Laden and other key terror figures.