Apr 15, 2013; Boston, MA, USA; Ambulances line the streets near Copley Square following multiple bomb blasts near the finish line of the Boston Marathon. Mandatory Credit: Michael Ivins-USA TODAY Sports
(AP) - A law enforcement official says cellphone service has been shut down in the Boston area to prevent any potential remote detonations of explosives.
Authorities have not identified what caused the explosives that erupted at the finish line of the Boston Marathon. The official was speaking on condition of anonymity because the investigation was ongoing.
The explosions have killed two people and injured at least 23 others.