According to CNN.com the Homeland Security Department has asked authorities
in many major cities Thursday to heighten security of major transportation systems
after the terrorist attack on London transit system.
Department spokesman Brian Roehrkasse said "We do not have any intelligence
indicating this type of attack is planned in the United States,"
In Washington, bomb-sniffing dogs and armed police were patrolling subways and
buses and looking for anything suspicious. Passengers are being urged to report
any suspicious activity. About 1.2 million people a day ride Washington's buses
and trains.