Spectators for the race, held annually on Patriots Day, were rushed to medical tents for treatment following the blasts. WBZ reported one of them happened near the viewing stands on Boylston Street, and there were multiple injured people.
Reuters stated via Twitter a spokesman for the marathon said the headquarters have been locked down. A CNN producer reported members of the crowd were injured when a pair of explosions happened, and medics are on the scene giving assistance.
Josh Cox, the U.S. 50K record holder, tweeted for people not to go near the finish line after explosions in buildings along with a picture from nearby the scene.