Boston Marathon explosions kill at least three – in pictures

Runners continue to run towards the finish line of the Boston Marathon as a blast hits spectators near the finish line of the race Photograph: Dan Lampariello /Reuters

A runner and race officials react to an explosion during the Boston Marathon Photograph: MetroWest Daily News/Ken McGagh/Reuters

Police officers with their guns drawn hear the second explosion down the street. The first explosion knocked down runner Bill Iffrig, 78, at the finish line
Photograph: Boston Globe via Getty Images

Spectators scattr in panic at the tThe Patriots' Day marathon – a highlight in Boston's sporting calendar and a public holiday Photograph: David L. Ryan/The Boston Globe/AP

Race officials run for shelter as the explosion rocks the finish line Photograph: John Tlumacki/AP

Police struggle to remove barricades to reach the victims of the first explosion Photograph: Boston Globe/Boston Globe via Getty Images

An injured man, clothes in shreds, leaves the site of the bombing Photograph: Kenshin Okubo/The Daily Free Press /AP

Injured people and debris lie on the sidewalk Photograph: Ken McGagh/MetroWest Daily News/AP

Medical workers aid the injured Photograph: Charles Krupa/AP

An injured woman is assisted; over 100 more were injured and at least three died Photograph: John Tlumacki/The Boston Globe/AP

The scene after emergency services had cleared spectators and the injured Photograph: Scott Eisen/Reuters

Medics work outside the triage tent in the aftermath of the two blasts Photograph: Elise Amendola/AP

A woman speaks with a police officer near the marathon route Photograph: Kenshin Okubo/The Daily Free Press/AP

Emergency services help an injured woman on a stretcher Photograph: Jeremy Pavia/AP

Runners and race officials look for loved ones near the finish line Photograph: Neal Hamberg/Reuters

Injured spectator taken away from the scene in a wheelchair Photograph: David L. Ryan/Boston Globe via Getty Images

Public safety officials evacuate the scene Photograph: Neal Hamberg/Reuters

Bomb-disposal experts investigate the Boylston Street explosion site Photograph: Jessica Rinaldi/Reuters

Barack Obama makes a statement in the White House briefing room Photograph: Win McNamee/Getty Images

Unclaimed finish-line bags near the blast site Photograph: Spencer Platt/Getty Images