Breaking News: Explosions At Boston Marathon - Ground Footage (Boston On Lockdown)
It happened around 2:45 p.m. outside Marathon Sports on Boylston Street, according to WBZ-TV's Lisa Hughes, who was near the scene covering the marathon.
There were two "incredibly powerful explosions just seconds apart," assumed to be bombs.
Some people were reportedly missing limbs. Others had blood on their heads.
"There's a lot of blood" at the scene, according to WBZ-TV producer Ken Tucci, who reported seeing more than ten people taken away from the scene on stretchers.