Some pictures from the scene:
The New York Times has a rough map of where the explosions took place:
While the official cause of the explosion is unknown, law enforcement officials tell NBC News that small homemade bombs may be responsible. Police have found at least two more devices, which are being dismantled. Police are also asking people on scene not to use cell phones out of fear that they could set off other devices.
Police scanner reports also indicate the presence of multiple suspicious devices and bomb dogs are now being brought in. The Lenox Hotel and the Prudential Center (Boston’s second tallest building) has been evacuated. An AP reporter also says that Newtown families were in the VIP section, by the explosion, but were not injured.
Massachusetts General Hospital has at least 10 patients with amputations and blown off limbs. The Director of Emergency Services describes the injury as “from a war zone.” More patients are en route.
New York Police say they are increasing security in response to today’s tragedy. In Washington D.C., the Secret Service is “beginning to cordon off Pennsylvania Avenue” and tightening security around the White House.
The White House says that President Obama has been notified of the incident in Boston and “His administration is in contact with state and local authorities. He directed his administration to provide whatever assistance is necessary in the investigation and response.” Obama received a briefing from Homeland Security adviser Lisa Monaco and other members of his senior White House staff.
A video from the scene: