This picture from Boylston Street in Boston appears to show two explosions near the finish line of the Boston Marathon.
The picture was tweeted by 90.7 RAV FM.
The smoke from the first
The second, at the base of the white building on the lefthand side of the street, appears to have happened at the moment this picture was taken.
The latest information on the Boston explosions is here >
The New York Times has plotted the location of both explosions here.