UPDATE/BOSTON (AP) - A person familiar with the situation tells The Associated Press that an 8-year-old-boy was among those killed in the explosions near the finish line of the Boston Marathon on Monday.
A person who spoke to a friend of the family says the boy's mother and sister were also injured as they waited for his father to finish the race.
Police say at least three people were killed in the blasts and more than 140 injured, at least 17 critically.
BOSTON (AP) - Police say at least three people have been killed in the explosions near the finish line of the Boston Marathon.
Police commissioner Ed Davis confirmed the three deaths but provided no details.
The explosions Monday also injured more than 130 people, knocking spectators and at least one runner off their feet.
Some of the victims lost arms and legs. Other injuries included broken bones, shrapnel wounds and ruptured eardrums.
BOSTON, Mass. -- One of the two dead is an 8-year-old child, a law enforcement official told NBC News.
BOSTON, Mass. -- According to the Associated Press, the Boston Police Commissioner says the JFK Library fire doesn't appear to be related to race explosions.
BOSTON, Mass. -- According to the Associated Press, the Boston Police Department says there has been a third explosion at JFK Library around 4:30 EST. They say they do not know if the explosions are related but are treating them as so at this time.
A law enforcement official says cellphone service has been shut down in the Boston area to prevent any potential remote detonations of explosives.
WASHINGTON (AP) - A senior U.S. intelligence official says two more explosive devices have been found near the scene of the Boston marathon where two bombs detonated earlier.
The official said the new devices were being dismantled.
It was not immediately clear what kind of devices had been found Monday. The official said the first two did appear to be bombs.
The official spoke on condition of anonymity because he was not authorized to discuss the findings publicly.
The official said it was not clear what the motive was or who may have launched the attack.
The Boston Police Department says 2 dead, 37 injured in 2 explosions near marathon finish line.
BOSTON (AP) - Authorities are investigating a report of two explosions at the finish line of the Boston Marathon.
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.
Jackie Bruno, a reporter for New England Cable News, said on Twitter that she saw people's legs blown off.
"Runners were coming in and saw unspeakable horror," she said.
Massachusetts General Hospital said that it had four patients and was expecting more.