Police crime scene investigators inspect the area outside 845 3rd Avenue in midtown Manhattan May 5. (Reuters)

New York City police shut down a portion of Third Avenue in Manhattan as they investigate two small makeshift grenades outside the British Consulate May 5. (Xinhua)

Various police officials fill the street outside a building on 3rd Avenue in midtown Manhattan May 5 after Two small makeshift grenades exploded outside the British Consulate. (Xinhua)

Two small makeshift grenades exploded outside the British Consulate in midtown New York early Thursday morning, causing no casualties. (Reuters)

Related story: Police questions man about British Consulate blast

    NEW YORK, May 5 (Xinhuanet) -- Two small makeshift grenades exploded outside the British Consulate in midtown New York early Thursday morning, causing no casualties, police said.

    The grenades filled with gun powder had been placed inside a cement flower box outside the front Midtown Manhattan building and went off at about 3:50 a.m. (0750 GMT), the local television NY1 quoted police officers as saying.

    Some windows of the building, where the British Consulate is housed, were shattered by the explosions and there was no damage to the structure of the building. Nearby streets were shut down.

    No suspects have been arrested and the police were looking at surveillance tapes, the report said, adding that no threats were received against the building beforehand.

    There has been no claim of responsibility for the explosion, which took place on the same day as the British general elections.

    "It is true the British Consulate is in that building but I don't think anybody should jump to conclusions," New York Mayor Michael Bloomberg told reporters at the scene. "We do not at this point have any idea who did it or a motive."

    The consulate is on the 9th and 10th floors of the building, the mayor said. He expected it would be open for business later in the day. Enditem