The U.S. Department of State announced on September 28 a Worldwide Caution stating that Americans traveling overseas should "review their circumstances carefully and to take any measures they deem necessary to ensure their personal safety" due to heightened concerns about the potential for terrorist activity against American citizens and interests.
The Department will continue to develop information about potential threats to Americans overseas and to share with them credible threat information through its Consular Information Program documents, which are available at http://travel.state.gov.
The warning says: "U.S. citizens and interests abroad may be at increased risk of terrorist actions from extremist groups. In addition to information included in country-specific documents, we recently advised that we had unconfirmed information that terrorist actions may be taken against U.S. military facilities and/or establishments frequented by U.S. military personnel in Korea and Japan. We also remain concerned about information we received in May 2001 that American citizens may be the target of a terrorist threat from extremist groups with links to Osama bin Ladin's Al-Qaida organization. These individuals have not distinguished between official and civilian targets.
"In light of the above information, U.S. Government facilities worldwide remain at a heightened state of alert. U.S. Government facilities have and will continue to temporarily close or suspend public services, as necessary, to review their security posture and ensure its adequacy. In those instances, U.S. Missions will make every effort to provide emergency services to American citizens. "
Countries for which travel warnings have been issued since September 11 include Niger, Indonesia, Tajikistan, Pakistan, Kyrgyz Republic, Turkmenistan, and Yemen.