Reporter describes filming 'horrific' Boston explosions

David Abel of the Boston Globe has spoken to the BBC about the scene he filmed at the finish line of the Boston marathon as two blasts erupted.

He was filming runners as they finished the race when he heard the "boom" and "immediately knew it was an attack".

Three people were killed and at least 150 injured in two explosions at the finish line of the Boston Marathon, police say.

The cause of the explosions has yet to be identified.

Footage courtesy Boston.com