Obama Calls Boston Bombings ‘Terrorism’ in Second Briefing (Video)

Obama calls the "heinous and cowardly" attack that killed three and injured over 140 others an "act of terrorism" but still does not know who was behind it

President Barack Obama addressed the Boston Marathon bombing again on Tuesday morning, calling it not only "a heinous and cowardly act" but an act of terrorism.

"Given what we now know about what took place, the FBI is investigating it as an act of terrorism," the president said. "Any time bombs are used to target innocent civilians, it is an act of terror. He avoided the word "terrorism" during his address to the nation on Monday.

Also read: President Obama on Boston Bombings: Perpetrators Will 'Feel the Full Weight of Justice'

But despite the new label, he said investigators still who was behind the two explosions that left three dead and over 140 injured. "What we don't yet know, however, is who carried out this attack or why," Obama said. "Whether it was planned and executed by a terrorist organization — foreign or domestic –or was the act of a malevolent individual."

But what he does know, he said, is "that the American people refuse to be terrorized." 

He also praised first responders, doctors and marathon runners for reacting to the tragedy with heroic "kindness, generosity and love."

Here's the president's second statement: