Multiple reports on Monday said there were one or more explosions at the Boston Marathon finish line, near Copley Square.
Photos posted to Twitter showed a large fiery explosion reaching as high as two stories.
Two massive explosions at finish line.
— Sean Kelly (@SeanKellyTV) April 15, 2013
Update (3:30 p.m.): According to The Associated Press, the first explosion happened about three hours after winners crossed the finish line on the on the north side of Boylston Street. The second explosion happened just a few seconds later.
“I saw people’s legs blown off. Horrific. Two explosions. Runners were coming in and saw unspeakable horror,” NECN’s Jackie Bruno wrote on Twitter.
Update (4:00 p.m.): You can track the last known location of runners in the Boston Marathon here.
Update (4:00 p.m.): Former Boston Police Commissioner Bratton reports that up to 50 people were injured in the explosions.
Update (4:10 p.m.): Boston Police Department told CBS News that at least 2 people were killed, 22 injured. Boston Marathon officials released a statement describing the explosions as having been caused by bombs.
Update (4:15 p.m.): NBC News reports that a “small homemade bomb is preliminary cause of explosion.”
Update (4:15 p.m.): According to the AP, families of Newtown victims were sitting near where the explosion occurred, but no reports of injuries.
Update (4:32 p.m.): A government official told CBS News that authorities were working under the assumption that the explosions were caused by bombs. “Hell yes, what else would they be?” the official said.
Update (4:35 p.m.): In a statement, Massachusetts Gov. Deval Patrick said that “this is a horrific day in Boston. My thoughts and prayers are with those who have been injured” and “our focus is on making sure the area around copley square is safe and secure/”
Update (4:37 p.m.): Some victims have been taken to Brigham Women’s Hospital.
Update (4:40 p.m.): Federal officials tell CBS News that the explosive devices were placed in trash cans. One explosive device has reportedly been recovered.
Update (4:55 p.m.): At a press conference, authorities announced two hotlines. Families of victims can call 617-635-4500. Anyone with tips can call 1-800-494-TIPS.
Update (5:10 p.m.): Officials now say 49 people have been injured and two have died.
Update (5:35 p.m.): Tufts Medical Center said Boston police had evacuated its emergency department as a precaution.
Police have also said a fire at JFK Library appeared to be unrelated to the attack on the Boston Marathon. Officials believe it was an electrical fire.
Update (5:50 p.m.): The Tufts Medical Center’s emergency department has re-opened after being temporarily evacuated. “To set things straight: No explosion occurred at Tufts MC, just suspicious item found, cleared by BPD. ED now normal operations,” the hospital stated on Twitter.
Update (6:15 p.m.): At a press conference, President Barack Obama said it was unclear “who did this or why.” He warned the country against jumping to conclusions regarding potential suspects and vowed that those responsible would “feel the full weight of justice.”
Update (7:10 p.m.): Officials now say an 8-year-old was among two killed by the bombs. The number of injured has risen to at least 110 individuals. Eight of those individuals are reportedly children.
Update (8:05 p.m.): The Boston Globe reported that police are questioning a person of interest at Brigham and Women’s Hospital.
Update (8:45 p.m.): The Boston Athletic Association has released the following statement:
The Boston Athletic Association extends its deepest sympathies to all those who were affected in any way by todays events.
Today is a sad day for the City of Boston, for the running community, and for all those who were here to enjoy the 117th running of the Boston Marathon. What was intended to be a day of joy and celebration quickly became a day in which running a marathon was of little importance.
We can confirm that all of the remaining runners who were out on the course when the tragic events unfolded have been returned to a community meeting area.
At this time, runners bags in Boston which remain unclaimed may be picked up by runners presenting their bib number or proof of race participation at the Castle, at 101 Arlington Street, in Boston.
At this time, we are cooperating with the City of Boston, the Commonwealth of Massachusetts, and all federal law enforcement officials.
We would like to thank the countless people from around the world who have reached out to support us today.
Update (9:00 p.m.): At a press conference, Boston Police Commissioner Ed Davis clarified that those being questioned at Brigham and Women’s Hospital were not suspects. He also said the number of dead had risen to three.
Watch the live video below from CBS Boston:
Watch this video of the explosion, uploaded to Vine on April 15, 2013.
Watch this video from The Boston Globe.