Explosions at Boston Marathon

There was tragedy as two powerful explosions caused chaos at the Boston Marathon, leaving dozens of people hurt.

One witness said, "Oh my god, they're dead!"

Footage was caught on camera of the moment one of the powerful explosions went off near the finish line of the legendary race, showing smoke rising and police scrambling to get to the injured.

One remarkable photo shows the moment of the blast as orange flame rises above the crowd.

The injured could be seen lying on the ground, some conscious, some unconscious. Some people were trapped under the mangled metal scaffolding.

Ambulances rushed the injured to nearby hospitals. Police believe the explosions may have been caused by bombs planted in trash cans near the finish line.

The explosions happened about three hours after the winners crossed the finish line when the bulk of runners were finishing the race.