BOSTON, Massachusetts: Boston police said Monday that what was initially thought to have been a third explosion in the city near the John F. Kennedy Presidential Library had in fact turned out to be a fire.
Shortly after twin blasts at the city's annual marathon killed at least two people, Police Chief Ed Davis told a press conference that a further blast had occurred at the library.
However, the Police Department later issued an updated statement on Twitter in which it said the "JFK incident appears to be fire related," and Davis also said the third incident was not linked to the two earlier explosions.
While there is yet no official word on whether the blasts at the marathon were an act of terrorism, New York and other cities took extra precautions.
Police in the nation's capital of Washington, DC -- which like New York was a target of the September 11, 2001 terrorist attacks -- have also "heightened security," spokeswoman Saray Leon told AFP.