Obama: ‘Evil’ Boston attacks were act of terrorism

"Evil." "Heinous." "Cowardly." President Barack Obama on Tuesday sharply denounced the Boston Marathon bomb attacks even as he held up the heroism of first responders and ordinary Americans in their bloody aftermath. And he urged the public to help authorities hunt down the culprits.

"This was a heinous and cowardly act, and given what we now know about what took place, the FBI is investigating it as an act of terrorism," the president said in the White House briefing room. "Anytime bombs are used to target inncoent civilians, it is an act of terror."

"What we don't yet know, however, is who carried out this attack or why, whether it was planned and executed by a terrorist organization, foreign or domestic, or was the act of a malevolent individual," he said. "Clearly, we are at the beginning of our investigation. It will take time to follow every lead and determine what happened—but we will find out."

"We will find whoever harmed our citizens, and we will bring them to justice."

Obama also ordered American flags flying over government facilities at home and overseas to be lowered to half-staff. Aides lowered the Stars and Stripes fluttering in the overcast Washington sky over the White House and the adjacent Eisenhower Executive Office Building.