BOSTON -- Rescue crews in Boston are on the scene of at least two explosions that ripped through crowds in Downtown Boston. Boston Police Commissioner Ed Davis also confirmed a third incident at JFK Library in Boston. At least two people are dead and more than 20 are injured. Boston authorities are reportedly talking to a person of interest following the blasts. Sources confirm to Fox News they have that person in custody.
Witnesses describe seeing a huge cloud of smoke billowing into the air near the Boston Marathon finish line. Authorities have evacuated the area and say the section of Boylston Street is still considered a danger zone. There's word of perhaps one or two more unexploded devices.
There are reports that several people may have lost limbs in the blast. There's a big area of a sidewalk that's spattered with blood. Emergency crews are taking injured to nearby hospitals. The finish line of the marathon is near the epicenter of downtown Boston.
One woman is describing the chaos after two explosions rocked the Boston Marathon.
A recording of a teleconference call with Vice President Joe Biden reveals his initial reaction to the explosions at the finish line of the Boston Marathon.
New York City is one of several cities ramping up security after a series of explosions tore through crowds in Boston. San Francisco also put its police on heightened alert. Officials in Washington, DC tell NBC News security is being increased on Pennsylvania Avenue in front of the White House.
Officials in Boston are urging people to stay out of the streets. Massachusetts Governor Deval Patrick urged tourists to return to their hotel rooms and residents to return to their homes. Authorities described the explosions as an "ongoing event" and urged caution.