© Agence France-Presse/Getty Images/Mandel NganPresident Barack Obama speaks on the shootings in Aurora, Colorado at what was scheduled originally as a campaign event on July 20, 2012 in Fort Myers, Florida.
U.S. President Barack Obama had intended to spend July 19 campaigning in Florida, but his plans changed the moment he learned alleged gunman James Holmes, 24, killed 12 people and injured 38 more during an early Friday screening of The Dark Knight in Aurora, Colorado.

Addressing the nation from the Harborside Event Center in Fort Myers, Florida, Obama, 50, did his best to make sense of Holmes' mass killing spree. "This morning we woke up to news of a tragedy that reminds us of all the ways that we are united as one American family," he said. "The federal government stands ready to do whatever's necessary to bring whoever is responsible for this heinous crime to justice."

"We will take every step possible to ensure the safety of all of our people. We're going to stand by our neighbors in Colorado during this extraordinarily difficult time."

Obama, 50, then informed the nation he had spoken with Aurora, Colorado mayor Steve Hogan and Colorado governor John Hickenlooper prior to his televised speech.

"Even as we learn how this happened and who's responsible, we may never understand what leads anybody to terrorize their fellow human beings like this. Such violence, such evil, is senseless. It's beyond reason," Obama said. "While we will never know fully what causes somebody to take the life of another, we do know what makes life worth living."

"The people we lost in Aurora loved and they were loved. They were mothers and fathers. They were husbands and wives, sisters and brothers, sons and daughters, friends and neighbors. They had hopes for the future and they had dreams that were not yet fulfilled. If there's anything to take away from this tragedy it's the reminder that life is very fragile. Our time here is limited and it is precious. What matters at the end of the day is not the small things, it's not the trivial things which so often consume us and our daily lives. Ultimately it's how we choose to treat one another and how we love one another."

Obama concluded: "I'm sure many of you who are parents here had the same reaction I did when I heard this news. My daughters go to the movies. What if Malia and Sasha had been in the theater, as so many of our kids do every day? Michelle and I will be fortunate enough to hug our girls a little tighter tonight, and I'm sure you will do the same with your children. For those parents who may not be so lucky, we have to embrace them and let them know we will be there for them as a nation."

The President has canceled his afternoon campaign commitments and will return to Washington, D.C. According to campaign spokesman Jen Psaki, Obama "feels this is the appropriate step on that front, and today we are focused on remembering the victims and finding out what happened."