(CNN)– President Barack Obama said he ordered the "full resources" of the federal government to respond to the Boston bombings on Monday, and that he also called for increased security around the United States as necessary.
"We still do not know who did this or why," he said from the Brady Press Briefing Room, cautioning people against jumping to conclusions. "But make no mistake, we will get to the bottom of this, and we will find out who did this, we'll find out why they did this."
Any individuals or groups responsible for the "senseless" bombing, he added, will "feel the full weight of justice."
"The American people will say a prayer for Boston tonight," he said.
Notably absent from his remarks was the word "terror," though federal investigators are classifying the bombings as a terror event. It is not clear if it's from a domestic or foreign source, a federal law enforcement official with knowledge of the investigation said.
Full transcript: Obama reacts to 'senseless' bombings
"Today is a holiday in Massachusetts, Patriot's Day. It's a day that celebrates the free and fiercely independent spirit that this great American city of Boston has reflected from the earliest days of our nation, and it's a day that draws the world to Boston's streets in a spirit of friendly competition," he said. "Boston is a tough and resilient town, so are its people. I'm supremely confident that Bostonians will pull together, take care of each other, and move forward as one proud city and as they do, the American people will be with them every single step of the way."
After Obama's statement, a White House official said "any event with multiple explosive devices – as this appears to be – is clearly an act of terror, and will be approached as an act of terror."
"However, we don’t yet know who carried out this attack, and a thorough investigation will have to determine whether it was planned and carried out by a terrorist group, foreign or domestic," the official continued.
According to the president's Facebook page, an organized call-in event scheduled for Tuesday has been postponed.
"Due to the events at the Boston Marathon, we are postponing tomorrow's National Call Day on gun violence prevention. Our thoughts and prayers are with everyone in Boston," his Facebook stated.
The event, run by the advocacy group Organizing for Action, would have organized supporters to call their senators and urge them to support the current gun legislation bill.
Over on Capitol Hill, House Speaker John Boehner led a moment of silence on the House floor for victims in Boston.
And a press conference to roll out the so-called Gang of Eight's immigration plan has also been postponed, according to Democratic Sen. Chuck Schumer of New York.
Vice President Joe Biden, meanwhile, was on a conference call earlier in the day about the Senate legislation to combat gun violence when he heard about the explosions.
"As I'm speaking here, they just turned on the television in my office and apparently there has been a bombing– I don't know any of the details of what caused it, who did it–I don't think it exists yet but our prayers are with those people in Boston who have suffered injuries," he said. "I don't know how many of them there are. I'm looking at it on television now."
- CNN's Tom Cohen, Jessica Yellin and Deirdre Walsh contributed to this report.
Of course he didn't use the word "Terror"; that would offend the Arab world. Instead he would rather tax us to death and say this was "A serious disagreement" which will yield no prosecutions and no one will be held accountable. Obama, this is your 9/11, the whole world is watching. Keep talking too long and no one will take you seriously. The whole world knows under your leadership that nothing is worth fighting for unless its with drones.
I don't give a flying fig what he calls this bombing. It was a horrible act and they're investigating it. Stop trying to stir up trouble and be a responsible reporter.
Obama is sane unlike Bush. After so many crazy shootings in the US if he starts listing Americans as terrorist then imagine.... Maybe this one was from just another American who is mentally unstable. Lets wait for investigation to be complete before jumping to conclusions.
If it was terrorists they should be embarrassed. A 13 year old with a semi-auto can and has done worse.
Just askin'... maybe it's just the rest of us, but it would seem that this president learned from the failures of the previous president; namely, making rash calls on his own that got thousands of our people murdered AFTER the last bombing. And for all we know, this is one of our own citizens– so encouraging the hatorade is only fuel on the fire.
Why does it matter what word is used to describe the same thing? Murder is murder no matter what you call it. For those that get hung up on whether someone uses the word terrorist or not, get a life. Lets stick together and find out who did this and make them pay!
@ Just Askin.. dude, stop complaining and start helping. We need to find the group/person that did it and help those who are impacted by it and help them move forward.
God bless the fallen. All of Kansas is ready to help.. just give us the word and we will do it.
Man, such venom. Is that helpful? It was a statement of support and information, stating our country is engaged with the investigation on a local, state, and national level. Would you have preferred silence?
You mean there are other ways to kill than just using guns? I guess Obammy should push for a ban on bombs now....
Oh wait, they're already illegal.
Thoughts and prayers to Boston tonight.
I don't get it. Our president seems to steer clear of certain words or groupings of words (heaven forbid) he might actually offend some offensive people. It's not him exclusively however, it's seeming to be our society as a whole. In the main article about this "terrorist act" on this site, I noted the usage of "event" at least two times.
Your Prez has his hands full now. Why not declare this another act of terrorism or is your Prez afraid to offend those that are attacking us on our own soil?
He didn't say the word "terror". Ohhhhhhh–seriously! You media people and talking heads are hilarious. Having to fill a 24-hour news day really leaves you guys desperate for something to talk about.
I just hope that President Obama responds to this better than he did for Benghazi.
OMG, he didn't use the word "Terror"!!! He must not care about those people if he doesn't use that word. Sorry he didn't use the word that CNN feels is much better for press and ratings.
So many libs blamed Bush for 9-11. Why is it not fair to blame Obama for this?
I'll be sponsoring national call day to stop bomb violence tomorrow
Almost the exact same words after the Benghazi attack!