A White House official said any event that features multiple explosive devices, as the Boston case appears to be, is clearly an act of terror and will be dealt with as an act of terror. He, however, said it was not yet known who carried out the attack and a thorough probe was required to ascertain whether it was planned by a terrorist outfit, foreign or domestic.
US President Barack Obama also said earlier that those responsible for the attacks were yet to be identified and asked people not to jump conclusions before all facts were gathered. He said the authorities would reach the bottom of the incident and find out the culprits and bring them to law.
Boston's police commissioner Edward Davis said the blasts were caused by powerful devices and they led to chaos in the heart of the city where several people had gathered on a holiday to witness a marathon featuring participants from 96 countries.
He said there had been two nearly simultaneous blasts, around 50 to 100 yards apart, and each of them had caused a large number of casualties. There was a third blast later, at the John F Kennedy Presidential Library down south. However, Davis said the third incident was not connected to the two earlier blasts.
At least three people were killed while more than 100 were injured [See here] in the explosions near the finishing line for the marathon. More than 100 people were admitted to Massachusetts General Hospital, Boston police sources said. Alasdair Conn, chief of emergency services at the hospital said such carnage is generally seen at times of war.
A surgeon at the hospital said eight people were in a critical state. Some of the victims lost limbs and many have suffered small metal debris or shrapnel injuries. The oldest patient is 71-year-old, hospital sources said.
Onlookers posted pictures on social networking sites showing blood on the sidewalks beside the finishing line on Boylston in the centre of the city, with victims lying on the ground. Local media sources said emergency officials had carried out a controlled detonation of a suspicious object later.