New York Police Department Officer Ariel Ortiz (L) looks into a train as he patrols the Times Square subway station in New York, July 7, 2005. Four blasts ripped through London at rush hour earlier in the day.
The United States is raising the terrorist threat level for rail and mass transit systems, but not for airlines, after the bomb blasts that tore through London's transit system. New York City is on heightened alert this morning. Authorities have stepped up security around subways, buses and transit stations.