D.C. Mayor Muriel Bowser and other officials are urging citizens to report any suspicious activity to the police.
ISIS delivered a new threat to the United States, claiming that it will carry out an attack on the nation's capital.
The terror group, which quickly claimed credit for the deadly Paris attacks last Friday, said that the carnage in France was just the beginning.
CIA Director John Brennan said the attacks in Paris should serve as a wake-up call for Americans.
“It's not just Europe. I think we here in the United States need to be obviously quite vigilant,” Brennan said during remarks at the Center for Strategic & International Studies Global Security Forum.
“Their agenda is to kill. Pure and simple,” added Brennan.
Security is ramping up across the country. There is a heavy police presence in Times Square, and U.S. Capitol Police sent a security awareness reminder to congressional offices today (ABC News)