US President Barack Obama delivers remarks on the Boston Marathon blasts, in the Brady Briefing Room of the White House in Washington DC, USA, 16 April 2013. Photo by EPA/BGNES
US President Barack Obama has described the bombing at the Boston Marathon as an "act of terror", adding that it was yet to be revealed whether it had been plotted by a foreign or domestic group or individual.
The two explosions near the finish line of the marathon on Monday killed three, including an 8-year-old boy, and wounded an estimated 176 people.
"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," Obama said Tuesday, as cited by Fox News.
"Any time bombs are used to target civilians, it is an act of terrorism," Obama noted in his second statement on the attack.
He urged Americans to be vigilant and to report suspicious activity.