NYC, DC Heighten Security Following Boston Marathon Explosion

New York City and Washington, D.C., have both implemented heightened security measures in the wake of two explosions that Boston Marathon Monday.

"We've stepping up security at hotels and other prominent locations in the city through deployment of the NYPD's critical response vehicles until is more about the explosion is learned," Deputy Commissioner of the New York Police Department Paul J Browne told CNBC.

Stepped up security measures have also been enacted at Pennsylvania Avenue in front of the White House, officials told NBC News. People with designated passes can still access the White House, but the public has been sent away.

The District's Metropolitan Police Department confirmed to NBC News that the police have implemented "heightened security" in the D.C. metro area.

In New York, the main focus according to reports will be on Manhattan hotels, (as that is where the Boston explosions took place), as well as stepped-up security in Times Square, at synagogues, bridges, tunnels, monuments and other landmarks like the Empire State Building and new Barclays Center in Brooklyn.

WCBS 880′s Peter Haskell reported more than a half-dozen NYPD cruisers were lined up along the streets of Times Square while members of the counter-terrorism unit were seen entering a Communication Division Command Post in Times Square. 

NYPD Commissioner Ray Kelly also weighed in, telling CBS News’ Scott Pelley, "we are in the crosshairs of terrorists and we don’t believe the threat has diminished very much."

"We don’t know the genesis of this, we don’t know who’s responsible for it, but we sort of have to have a 360-degree perimeter in this city."

“New Yorkers should be alert. We ask them to be aware of their surrounding and [if they] see anything suspicious, call our resources, call 911, call 311 if it’s not an immediate emergency,” he said.

In terms of the heightened security, Pelley said it is routine.

"This is what we do, we’ve done it in the past and we’re doing it right now."

TheBlaze national security expert Buck Sexton, who formerly served with the NYPD's terrorism unit, provided insight into the attack during his appearance on the Glenn Beck Program.

"It was clearly an attack. It was clearly a terrorist attack," Sexton stated.