Witnesses reported a huge plume of white smoke, followed by a chaotic scene of screaming and crying by spectators lining the street and the runners approaching the end of their grueling 26.2-mile race.
Jill Harmacinski, a reporter covering the race for The Eagle-Tribune of North Andover, Mass., said the explosions sounded like cannon blasts or gun shots. She said there was “blood all over Boylston Street” at and near the finish line.
“It was awful,” Harmacinski said. “Everybody was running away from the smoke, and many of them were covered in blood. It was a confusing and scary scene.”
President Barack Obama phoned Massachusetts Gov. Duval Patrick and Boston Mayor Thomas Menino after receiving a briefing on the situation from Homeland Security adviser Lisa Monaco.
“He offered the complete assistance of the FBI and all other federal agencies,” the governor announced at a news conference. “Every resource at our disposal will be used to bring those responsible for this ghastly act to justice.”
Obama on Tuesday said that the Boston Marathon bombings were “an act of terror” against civilians.
“It was a heinous and cowardly act,” the president said from a press conference at the White House. As to the perpetrators, Obama said: “We will bring them to justice.”
Obama ordered the flag above the White House lowered to half-staff, while inside he was huddling with top advisers, receiving the latest details on the investigation into the attack.
Obama also noted that Monday was Patriots Day, a state holiday in Massachusetts commemorating the battles of Lexington and Concord and the start of the American Revolution more than 235 years ago.
“Boston is a tough and resilient town; so are its people,” he said. “I’m sure the people of Boston will pull together.”
Almost 27,000 runners from 96 countries competed in the marathon, a signature event for Boston and the world running community.