Story highlights President Barack Obama said the Orlando shooting was "an act of terror and an act of hate"

It is the deadliest mass shooting in American history

Washington (CNN) President Barack Obama said federal law enforcement officials are investigating the mass shooting at a gay nightclub in Orlando as an act of terrorism.

"We know enough to say this was an act of terror and an act of hate," Obama said in a brief statement from the White House on Sunday afternoon. "The FBI is appropriately investigating this as an act of terror. We will go wherever the facts lead us ... What is clear is he was a person filled with hatred."

At least 50 people were killed and 53 more injured in the worst mass shooting in U.S. history early Sunday morning.

Obama said the shooting marked "an especially heartbreaking day for our friends who are lesbian, gay, bisexual or transgender."

"This is a sobering reminder that attacks on any American, regardless of race, ethnicity, religion or sexual orientation is an attack on all of us and on the fundamental values of equality and dignity that define us as a country," he said, "and no act of hate or terror will ever change who we are or the values that make us Americans."

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