There are multiple reports that there have been two separate explosions at the finish line of the Boston Marathon according to Business Insider. You can also see video from CNN below about the explosions.
The Boston Police Department is reporting that there was “some sort of incident at 671 Boylston Street”, which is the finish line for the race. They could not give out further information at the time of the call.
Reporters on the scene are reporting dozens of injuries and lost limbs. TV crews are showing images lots of blood on the ground.
Here is video of the 1st explosion.