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.
Boston police said that a 3rd explosion occurred at the John F. Kennedy Presidential Library and Museum in Boston after other blasts in the city near the finish line of the Boston Marathon.
Police spokeswoman Neva Coakley said "there has been another explosion at JFK."
Rachel Day, a spokeswoman for the John F. Kennedy Library, located about three miles from the marathon's finish line, said that there was a fire at the library but no one was injured.