A Boston police officer wheeled an injured boy down Boylston Street as medical workers carried an injured runner.

People ran away from explosions on Boylston Street, near the Boston Marathon finish line.

A man walked away from the scene of the explosions, his clothing ripped.

Two people were on the sidewalk as Boston police cleared Copley Square.

President Obama spoke about the attacks from Washington, D.C.

The window of Marathon Sports on Boylston Street was shattered.

The blasts happened on Boylston Street, where crowds gathered near the marathon’s finish line.

The area around the finish line was evacuated.

Justine Franco of Montpelier, Vt., held a sign near Copley Square looking for her missing friend who was running her first Boston Marathon.

A man carried an American flag near Kenmore Square.

Police officers with their guns drawn reacted to the second blast down the street.

A second explosion occurred seconds after the first.

Katherine Swierk (left) hugged her aunt Terry Days (center) and friend Jocelyn Cacio near Copley Square.

Runners gathered near Kenmore Square.

Two officials ran away from the first explosion on Boylston Street.

A runner (center) reunited with loved ones near Copley Square.

Cell phone service was disrupted in the area.

A State Police officer inspected a suspicious package on Stuart Street.

Two women walked away from the scene of the explosions.

Debris littered the area near the finish line.

Many injured were taken by stretcher to area hospitals.

A marathon volunteer helped a runner who was knocked to the ground.

Marathon volunteers at the scene.

Emergency personnel at the scene.

Boston Police struggled to remove barricades to reach victims.

A marathon runner walked through traffic at Boylston Street and Massachusetts Avenue.