“As we mark the 10th Anniversary of the September 11, 2001, terrorist attacks, the Department of State informs U.S. citizens traveling and residing abroad of the continued threat posed by al-Qa’ida and its affiliates. While we have not identified any specific threats from al-Qa’ida affiliates and allies to attack the United States or our interests on the 9/11 anniversary, U.S. citizens should be aware that al-Qa’ida affiliates and allies have demonstrated the intent and capability to carry out attacks against the United States and our interests around the world. In the past, terrorist organizations have on occasion planned their attacks to coincide with significant dates on the calendar. This Worldwide Travel Alert supplements the July 26, 2011, Worldwide Caution, and expires on January 2, 2012.
U.S. citizens traveling and residing abroad should enroll in the Smart Travelers Enrollment Program (STEP) at the following website: https://travelregistration.state.gov. U.S. citizens without internet access may enroll directly at the U.S. Embassy or Consulate at their destination. By enrolling, U.S. citizens make it easier for the Embassy to contact them in case of emergency. “
Source: 9-11 Anniversary Travel Alert