Boston police said two people were killed in the blasts. The Boston Globe reported that at least 64 people were injured.
Later, police confirmed that another explosion took place at the John F. Kennedy Library in Boston, and there were media reports that an undetonated device was found under a grandstand at the marathon.
According to the Globe, 19 injured people were initially transported to nearby Massachusetts General Hospital, six of them in critical condition.
Boston Marathon officials described the blasts near the finish line as originating from “two bombs.”
Police subsequently cleared the sidewalk on Huntington Street, saying there was a live bomb inside the Prudential Center.
Massachusetts Gov. Deval Patrick urged people to “stay out of crowds” as they made their way home.
A bomb squad used what were described as controlled explosions to detonate two other devices, the Associated Press reported.
A CNN producer who was at the race said the first large explosion was followed about 10 seconds later by another blast. He said he saw at least five or six people who appeared to be injured.
Emergency personnel rushed to the area, and the street was quickly sealed off.
The explosions occurred shortly before 3 p.m. Eastern time near the intersection of Boylston and Exeter streets. Local media reports said store fronts were blown out.
The Boston Fire Department, fearing secondary blasts, ordered all equipment off Boylston Street. A Boston firefighter tweeted that there were fears of “another possible device” at the city’s Mandarin Hotel, but this could not immediately be confirmed.
Nor was it immediately known what caused the blasts near the finish line.
According to the CNN producer, the blasts occurred on opposite sides of the street. He said the first “looked like it was off to the side of the street” and the second “looked like it happened on the sidewalk.” There were indications that one of the blasts may have come from a trash container, he said.
The witness said he saw at least four injured people being treated at the scene.
Many of the injured appeared to be spectators who were watching the race.
About half of the nearly 27,000 participants had reportedly finished the race when the blasts occurred. The racers came from at least 56 countries and territories.
“I saw two explosions,” reported Boston Herald journalist Chris Cassidy, who was running in the marathon. “The first one was beyond the finish line. I heard a loud bang and I saw smoke rising.” The blast “ looked like it was in a trash can or something,” he said. “There are at least a dozen that seem to be injured in some way.”
Source: The Washington Post