Islamic State's Amaq news agency said on Sunday that the Islamist militant group was responsible for the shooting that killed at least 50 people in a massacre at a gay nightclub in Orlando, Florida.
"The armed attack that targeted a gay night club in the city of Orlando in the American state of Florida which left over 100 people dead or injured was carried out by an Islamic State fighter," Amaq said.
Hatred of gays or IS links, what led to the worst mass shooting in US history?
President Barack Obama called the mass shooting an "act of terror" in remarks to the nation from the White House briefing room.
"We know enough to say this was an act of terror and an act of hate," he said. "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."
"This is an especially heartbreaking day for our friends who are lesbian, gay, bisexual or transgender," he said.
(With agency inputs)

Volunteers Lesie Jampolsky and Dee "Mamma Dee" Richer, console each other at the LGBTQ Community Center after the late night shooting at Pulse, an Orlando night club,on Sunday.