UPDATE 8: Use this thread to send well-wishes and to discuss.
UPDATE 7: NBC News reports that one of the deceased was 8-years-old.
UPDATE 6: This new video footage was taken from within the chaos on the street.
UPDATE 5: Boston Police Commissioner confirms "explosion" at JFK Library.
UPDATE 4: Official to NBC news: "Traumatic amputations at the scene... Legs blown off."
UPDATE 3: JFK Library fire reportedly unrelated.
UPDATE 2: Video of the explosions via TPM:
UPDATE 1: Fire reported at JFK Library in Boston. A third explosion has been heard but could be a controlled bomb squad detonation.
Two explosions at the finish line of the Boston Marathon have resulted in injuries.
Bloody spectators were being carried Monday to the medical tent that had been set up to care for fatigued runners. Police wove through competitors as they ran back toward the course.
“There are a lot of people down,” said one man, whose bib No. 17528 identified him as Frank Deruyter of North Carolina. He was not injured, but marathon workers were carrying one woman, who did not appear to be a runner, to the medical area as blood gushed from her leg. A Boston police officer was wheeled from the course with a leg injury that was bleeding.
About three hours after the winners crossed the line, there was a loud explosion on the north side of Boylston Street, just before the photo bridge that marks the finish line. Another explosion could be heard a few seconds later.