Report: Boston marathon bombed -- two explosions, many injured, at least three dead

Two explosions at the finishing line of the Boston Marathon killed at least three people and left at least a dozen more injured, according to news reports. Law enforcement officials said they were caused by small, home-made bombs.

Photos and videos posted within minutes by witnesses showed scenes of chaos and bloodshed, with emergency services swarming the scene on Boylston street and smoke billowing into the sky.

The organizers of the Boston Marathon reported that two bombs detonated seconds apart, about three hours after the front-runners crossed the finishing line. A third device was destroyed later in a controlled detonation. Flight restrictions were in force late Monday afternoon.

The death toll looks set to rise, with some sources already reporting many more dead, and police still working to evacuate streets near where the explosions took place.

Updates below, timestamps in Eastern.

~3:15 p.m.: the first photos are being posted to twitter (1, 2, 3)--WARNING for blood and dismemberment.

~3:20 p.m. -- Police report another device is in front of the Mandarin Hotel.

3:24 p.m. -- 90.7 RAV FM posted a photo of an explosion, and reported that media was "locked down at nearby hotel." -- Dean

3:27 p.m. Boston's WHDH.com has livestreaming coverage.

3:32 p.m. -- "Medical tents already full" ... "All victims off scene" [via]

3:35 p.m. -- "Everyone in the area needs to evacuate immediately. Danger zone, do not stay." [via]

3:40 p.m. -- WHDH's Janet Wu reports that the area has been completed evacuated due to the possibility of other devices. "about 40 minute ago, I was a half block away. ... It's unconfirmed, but it happened at 671 Boylston Street. ... The response was immediate because there were so many medical personnel in the area. ... My colleagues and I saw many many injuries and those injuries were severe."

3:41 p.m. -- CBS reports "at least a dozen" injured.

3:42 p.m. -- A vine video of the explosion itself from WHDH — Dean. And on YouTube.

3:50 p.m. -- The organizers of the Boston Marathon report that the explosions were caused by bombs, detonated seconds apart. A fire was reported at Boston's JFK library, though it's not clear if there is a connection.

3:54 p.m. -- "Officials: There will be a controlled explosion opposite the library within one minute as part of bomb squad activities." [via] CBS News: "Third bomb detonated by police" [via]

4 p.m. -- Three confirmed deaths, reports Fox. Boston Police, however, say 2 are dead and 22 injured. Boston.com says dozens are injured. The New York Post reports that 12 are dead.

5:34 p.m.: Google People finder, for anyone looking for missing persons in Boston. The Red Cross has an online register for people in Boston to let their loved ones know they are safe and sound. Here are other online tools people are using to connect. —Xeni.

5:41 p.m.: Multiple reports citing Boston police say JFK Library fire was not an explosion, but a fire believed to be unrelated to the marathon bombs. —Xeni

5:46 p.m. ET: Boston.com has a video from directly next to the finish line as the first explosion goes off. Certainly the highest quality video so far– this shows scale of it, the immediate reaction and you can hear the second blast. Warning, graphic. — Dean

5:46 p.m.: President Obama scheduled to speak at 6:10pm Eastern. CNN and CBS are among the news organizations now referring to this as a terrorist attack. —Xeni

7:02 p.m.: Hundreds of Bostonians offering free rooms in their homes for people affected by the bombings. —Mark

8:53 p.m.: Patton Oswalt brings some positive perspective, and reminds us that the good people here outnumber the bad and we always will. — Dean

8:41 a.m.: This Reuters piece from yesterday has a few details missing from other coverage I'd seen, including the fact that the bombs appear to have been filled with ball bearings and other shrapnel. — Maggie

8:51 a.m.: Mother Jones tells the amazing story of Carlos Arredondo, a first responder who was photographed helping victims of the bombings while wearing a cowboy hat. Arredondo lost his son, a Marine, in Iraq in 2004 and attempted suicide while he was still struggling with that grief. He survived and became a peace activist. Yesterday, he was at the Boston Marathon, saving lives. — Maggie

9:00 a.m.: WBUR Boston reports that police were on hand, searching an apartment belonging to "a person of interest" in Revere, Mass. early this morning. Revere is just north of Boston. In general, WBUR Boston is doing an amazing job of sober, responsible reporting. Their update feed is worth following. — Maggie

9:05 a.m.: "Marathons aren't a sporting contest, but a celebration of being alive. ... These people aren't our rivals or our enemies, they were our partners." Marathon runner Jeff Pearlman has written a deeply moving essay about what this tragedy means to the closely knit community of marathon runners. — Maggie