TSA Guidance for Passengers on Heightened Security Measures in Place Following Dec. 25 Incident [open pdf - 29KB]
"Today, the Transportation Security Administration [TSA] issued new security directives to all United States and international air carriers with inbound flights to the U.S. effective January 4, 2010. The new directive includes long-term, sustainable security measures developed in consultation with law enforcement officials and our domestic and international partners. Because effective aviation security must begin beyond our borders, and as a result of extraordinary cooperation from our global aviation partners, TSA is mandating that every individual flying into the U.S. from anywhere in the world who holds a passport issued by or is traveling from or through nations that are state sponsors of terrorism or other countries of interest will be required to go through enhanced screening. The directive also increases the use of enhanced screening technologies and mandates threat-based and random screening for passengers on U.S. bound international flights."
Transportation Security Administration: http://www.tsa.gov/