Here's video of the explosion:
Police are saying two people are dead and 23 are injured. A press conference is expected soon.
1:32 PM PT: Here's a New York Times map of the bombing locations.
1:33 PM PT: Fox in the past 30 minutes has had both Joe Arpaio and New Hampshire Senate Candidate Scott Brown on to offer their commentary on the bombings.
1:36 PM PT: This live feed should have the press conference when it happens. Unfortunately, you have to sit through a 30 second ad before connecting. The press conference hasn't started yet, so you might want to connect now if you plan to watch it:
1:38 PM PT: CBS says the devices exploded in trash cans. CBS also says they have a surveillance photo of a man with "a couple of backpacks" in the area before the explosions. They also say they have an unexploded device. CBS sources this to law enforcement, but that's no guarantee of accuracy.
1:49 PM PT:
MARATHON EXPLOSION: Toll rises to 2 dead, 64 wounded in Boston Marathon explosions.
— @GlobeMetro via HootSuite
1:51 PM PT: Governor Deval Patrick has opened the press conference and is now turning it over to Ed Davis, the Boston police commissioner.
1:52 PM PT: Davis says the explosions occurred 50 to 100 yards apart at 2:50 PM ET.
1:54 PM PT: There was a third incident that occurred, says Davis, citing an explosion at JFK Library. He says BPD does not know if the explosions were related, but is assuming that they were related. Davis is calling for people to stay home and inside. At this point they have not found any other devices, according to Davis.
1:55 PM PT: Anyone searching for a loved one should call 617 635 4500. Anyone with info should call 1 800 494 TIPS.
1:56 PM PT: So, Davis directly contradicted multiple reports of additional explosive devices having been found.
1:59 PM PT: Davis also says there was a controlled detonation on Boylston, but that doesn't conflict with what he said about finding other devices, because he says that every bag left at the scene was treated as suspicious. That could mean the controlled explosion was of those bags.