FBI investigating Boston Marathon blasts as ‘act of terrorism’: Obama

U.S. President Barack Obama says the FBI is investigating the twin bombings at the Boston Marathon as an act of terrorism.

“This was a heinous and cowardly act,” said Obama who will travel to Boston on Thursday. “Anytime bombs are used to target innocent civilians it is an act of terror.”

But he said Tuesday morning that officials still don’t know who set off the bombs or why, nor whether it was by a domestic or foreign organization or an individual.

He promised officials “will find whoever harmed our citizens and we’ll bring them to justice.”

Investigators continue to work to determine a motive and find the person or people who planted two bombs that killed three people, including an eight-year-old boy, and wounded more than 170 others at the Boston Marathon.

At a Tuesday morning news conference, Boston and Massachusetts state officials reiterated their resolve to bring the person, or people, responsible for the attack to swift justice and once again appealed to the public for photographs, video and witness accounts from the scene before and around the time of the explosions.

“The American public wants answers and the citizens of the city of Boston and the commonwealth of Massachusetts want and deserve answers,” FBI lead investigator Rick DesLauriers said.

“This remains a very active investigation. … However, there are no known additional threats. We continue to interview various witnesses and process the crime scene.”

Read full coverage of the Boston Marathon attack

Investigators searched a suburban Boston apartment complex for more than eight hours on Monday night. DesLauriers wouldn’t say if authorities have anyone in custody.

Massachusetts Gov. Deval Patrick dispelled rumours that other undetonated explosive devices were found at the scene.

“Two and only two explosive devices were found yesterday,” he said.

“There were no unexploded explosive devices found.”

Boston Police commissioner Edward Davis said there were a total of 176 casualties, including the three people killed. Seventeen people are listed in critical condition.

At a separate news conference on Tuesday morning, doctors at Massachusetts General Hospital said they’re treating bombing victims who were hit by small pieces of metal and other fragments, including pellets and nails. Four amputations have been performed on victims at that hospital. Doctors from Boston’s Brigham and Women’s Hospital also said patients are being treated there who had been hit by projectiles that were part of the explosive device. Patients there range in age from 16 to 62.

The Associated Press reported Tuesday that a six-litre pressure cooker was used in at least one of the bombs. One of the bombs sprayed metal shards and ball bearings, and the other nails.

Pressure cooker bombs have been used in Afghanistan, Pakistan, India and Nepal, the AP reported, citing a 2010 government intelligence report.

No individuals or groups have claimed responsibility for Monday’s attack.

Eight-year-old Martin Richard was among those killed in the twin explosions that happened on Boylston Street around 2:50 p.m. near the marathon finish line. His father Bill Richard, who was running the race, released a statement on Tuesday.

“My dear son Martin has died from injuries sustained in the attack on Boston. My wife and daughter are both recovering from serious injuries. We thank our family and friends, those we know and those we have never met, for their thoughts and prayers,” he said.

His wife suffered a brain injury and his daughter lost a leg.

More than 2,000 Canadians were registered to take part in the race. Foreign Affairs said late Monday no Canadians appear to be among those killed or hurt.

The explosions happened just past the four-hour mark of the historic race. More than 15,000 people had already completed the marathon by that point, but thousands of recreational runners were still on the course.