Chaos as twin blasts rock Boston Marathon
Two bombs that exploded in the crowded streets near the finish line of the Boston Marathon have killed at least three people, including an eight-year-old boy, and injured at least 176 in a bloody scene of shattered glass and severed limbs that raised alarms that terrorists might have struck again in the US.
The Boston Globe named the boy who died as Martin Richard, from Dorchester in Boston, and reported that his mother and sister had suffered grievous injuries in the attack. A third child was uninjured.
Boston Police Commissioner Ed Davis said no suspects were in custody but "we are questioning many people". Investigators were reviewing streams of video gathered from nearby security cameras.
People were told to stay out of the city as it was announced the FBI had taken over the investigation into the blasts. They occurred just before 3pm local time (5am AEST) and went off within 100 metres of each other near Copley Square in what appeared to be a co-ordinated attack.
Eight children are among the injured, including a two-year-old boy in intensive care with head injuries. At least 10 people have had limbs amputated. No one has claimed responsibility for the carnage.
Richard DesLauriers, the special agent in charge of the FBI's Boston office, said the bureau was treating the inquiry as "a criminal investigation that is a potential terrorist investigation".
It has been suggested the bombings may have been timed to cause maximum damage, with both blasts occurring when the largest proportion of runners were due to cross the finish line.
Early reports suggested five unexploded bombs had been found near the finish line but by nightfall, authorities were saying no other explosive devices had been found. As many as seven suspicious packages had been destroyed but they were later found not to be bombs.
The two bombs that went off at the finish line were described by one of the officials as relatively small and possibly containing small ball-bearings or BB gun pellets, designed to serve as shrapnel. It was unclear whether the devices were remotely detonated or included timers, the official said, adding that no conclusions had been drawn on whether a group or lone wolf had been responsible for the attack.
Injuries from the two explosions ranged from cuts and bruises to lost limbs. Many people suffered lower-leg trauma and shrapnel wounds, while some suffered ruptured eardrums.
There were reports that ball-bearings had been pulled from victims' bodies. The Boston Globe reported victims had been brought to hospital with metal debris embedded in their bodies, debris which doctors did not think was shrapnel from the bombs.
"This is the sort of carnage you expect to see in war," said Alasdair Conn, chief of emergency services at Massachusetts General Hospital, where 22 victims were taken, six of them critical, including four with traumatic amputations.