The New York City police issued a statement at 7:33 a.m. describing the source of the explosion as an “improvised explosive device” and putting the time of the blast at 3:43 a.m. The authorities are looking into a possible connection to two earlier bombings at foreign consulates in Manhattan, in 2005 and 2007. Subways and traffic are running normally through Times Square.

The authorities were looking into whether the explosion was connected to two earlier blasts that were similar in method and timing, the official said. At about 3:40 a.m. on Oct. 26, 2007, two dummy hand grenades that had been fashioned into crude bombs exploded outside the Mexican Consulate at 27 East 39th Street in Murray Hill, shattering windows. The building was not occupied and no one was hurt. At 3:55 a.m. on May 5, 2005, two crude but powerful explosive devices detonated outside the British Consulate at 845 Third Avenue in East Midtown, shattering windows and damaging a planter.