Here is a text of official report about U.S.:
All Americans, including those traveling in the transportation systems, should continue to be vigilant, take notice of their surroundings, and report suspicions items or activities to local authorities immediately.
Everybody should establish an emergency preparedness kit as well as a communications plan for themselves and their family, and stay informed about what to do during an emergency situation.
Originally posted: http://www.dhs.gov/dhspublic/display?theme=29
Travel to Russia!