Tragedy struck the Boston Marathon today, in the form of a pair of bombs that exploded in a densely populated area close to the finish line at Copley Square. At least 2 people have died and at least 2 dozen are injured. The New York Post has reported a much higher casualty total as of this writing.

A pair of devices exploded a block apart. At least one more device was found undetonated in the area. A thread on the tragedy is ongoing on the Slowtwitch reader forum, so that reports by readers in the area can be posted, and announcements about those in the Slowtwitch community running the race can be made.

News reports first described the blasts as “explosions”, and a statement by race officials was the first account to identify the explosions as bombs. The injuries are severe, which include lower leg trauma, including the loss of limbs.

The explosions occurred roughly 4hr9min into the race.

UPDATE 2PM Pacific: Boston Police verify another device detonated at the JFK library, and a third device proximate to the 2 devices in Copley Square was exploded by police.

A police spokesman was asked during a press conference whether this was a terrorist attack, and he responded, "You can reach your own conclusions."

UPDATE 6:30PM Pacific: A third person is confirmed dead by Boston Law Enforcement, and the incident at the JFK library has been called an unrelated fire. The number of those reported injured has increased to 100 or more.