At least two people were killed and 22 others hurt in two blasts at the site of the Boston Marathon in the US today.
The explosions occurred more than two hours after the first of the race's nearly 27,000 runners had crossed the finish line.
"Blasts near the finish line of the Boston Marathon killed two people," Boston police said.
The race was halted as was subway service into the area.
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.
Footage from local television outlets showed runners and spectators escaping the scene after the explosions were heard near the roads.
The explosions sent smoke billowing into the air at Copley Square, turning a site of celebration into a mess of destruction, CNN reported.
Crowds had gathered in the area to watch the runners. Out of an abundance of caution, the Lenox Hotel was evacuated, the Boston Globe reported, as authorities looked into possible security concerns.
Officials in other cities, including New York, tightened security as as result.
Mike Baingon, who works at the Atlantic Fish Company in Boston, said an explosion took place in front of the restaurant and that he was right by the front door at the time.
Thousands of people participate in the Boston Marathonm which is an annual marathon hosted by several cities in Greater Boston in eastern Massachusetts.
It is always held on Patriots' Day, the third Monday of April.
