UPDATE 6:15 PM:
Two people died in Monday's terrorist attack at the Boston Marathon.
The Boston Globe confirmed that an 8-year-old boy is one of the two people who died.
The President was unwilling to call the bombing a terrorist attack during his statement on Monday afternoon, but a White House official classified it as a terror attack on Monday evening.
UPDATE 3:50 PM:
The Boston Globe reports the injury toll at the Boston Marathon Bombing has climbed to 64 wounded and 2 dead.
UPDATE 3:31 PM:
ABC News reports that Boston Police are asking people in the area of the bombing to avoid using cell phones for fear that they could trigger additional devices.
There are also reports that police have dismantled at least one additional explosive device.
UPDATE 3:08 PM
ABC News - Boston - Two explosions erupted the finish line of the Boston Marathon today, turning the annual race into a bloody crime scene.
The blasts occurred on Boyleston Street about three hours after the top runners had finished the race, but with thousands of marathoners still running the route.
According to law enforcement sources, the first blast was at the Marathon Sports running store before 3 p.m., and blew out windows in four nearby buildings, injuring at least 25 and killing 2.
About 10 second later, a second explosion occurred, severely injuring more bystanders, police said.
Boston EMS personnel could be seen shuttling the injured out of the blast area on wheelchairs. Several of them were bleeding from the face.
Massachussets Genreal Hospital has received four patients and is expecting more, according to a hospital spokesman.
A trauma nurse from the hospital told ABC News that the race's medical tent, already set up to deal with runner injuries, set up a morgue area at a triage center at the back of the tent. The medical staff reported multiple victims with severed limbs and children with severe burns.
Bomb squads are sweeping the area, checking suspicious packages and are testing for chemicals to help determine what kind of device was used, according to police.
Homeland Security Direction Eric Holder was in touch with the FBI in Boston and President Obama was notified of the blasts.
Police have told people in area to avoid trash cans, according to witnesses.
The explosions erupted on what is usually a festive day in Boston. It is designated Patriots Day and most offices are closed for the celebration and the marathon.
Debris from the explosions could be seen scattered throughout the spectators stands and finish line area of the marathon as emergency personnel cleared the area.
Video of the explosions showed plumes of white smoke pouring into the air above the street where runners were.
More than 26,00 runners were registered to compete in this year's marathon.