[Updated at 12:08 p.m.] Officials with Amtrak and Atlanta's subway system have both stepped up security efforts following a subway bombing in Moscow, Russia.
"Following the recent terrorist attack in Moscow, Amtrak employees are reminded to remain vigilant in their duties and attentive to their surroundings during daily work activities," Amtrak said in a statement. "While there is no specific threat to Amtrak identified at this time, Amtrak Police personnel assigned to the FBIâ€™s National and Regional Joint Terrorism Task Force remain informed regarding any potential threats and other security issues."
Atlanta's MARTA officials said they will be "increasing police presence and patrols" because of the attacks, but there are no credible threats of attack against the system.
[Posted at 10:03 a.m] Police are increasing security in the New York City and Washington D.C. subway systems as a precaution following Monday's subway bombings in Moscow, according to local authorities.
Explosive ordnance detection teams will conduct station and rail yard sweeps throughout the day as part of the heightened security in the Washington area, a statement from D.C. transit officials noted.
"We remain an open system and we do what we can to be as secure as possible," Metro Transit Police Acting Chief Jeri Lee said.
The Washington area metro system is also conducting a drill simulating a bus explosion on Monday. The drill has been planned since December, the statement said.
Earlier, New York Police Department Deputy Commissioner Paul Browne said police are stepping up security in the New York City subway system.