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(CNN) – Boston police are investigating whether a third explosion, at the John F. Kennedy Presidential Library, is connected to Monday’s two bombings at the Boston Marathon, Police Commissioner Ed Davis said.
Blasts near the finish line of the Boston Marathon killed two people and injured at least 28 others, Boston police said.
The marathon itself, on its Facebook page, referred to the blasts as bombs. Authorities did not say immediately what caused the explosions.
Massachusetts General Hospital said it was treating 19 injured people; Tufts Medical Center reported that some injured were to be treated there as well.
The explosions sent smoke billowing into the air at Copley Square, turning a site of celebration into a mess of destruction.
Out of an abundance of caution, the Lenox Hotel was evacuated, the Boston Globe reported, as authorities looked into possible security concerns.
Off icials in other cities, including New York
President Barack Obama telephoned Boston Mayor Tom Menino and Massachusetts Gov. Deval Patrick to express concern for those wounded in a pair of explosions that ripped through the crowd near the finish line of the Boston Marathon. Obama also offered Washington's help in the investigation and response to the incident. Boston police said two people were killed and 23 injured, amid news reports that the blasts were a bomb attack.
“Shortly after being notified of the incident around 3 p.m. EDT, the president received a briefing from Homeland Security adviser Lisa Monaco and other members of his senior White House staff in the Oval Office," a White House official told reporters on condition of anonymity. "The president called Boston Mayor Tom Menino and Massachusetts Gov. Deval Patrick to express his concern