ISIS Claim: Attack on 'Nightclub for Homosexuals Carried Out by Islamic State Fighter'

The ISIS-affiliated Amaq News Agency issued a statement claiming that Orlando nightclub shooter Omar Mateen was a fighter of theirs.

The claim was released minutes after President Obama, giving a statement in the White House briefing room, said the attack in which at least 50 people were killed was determined to be terrorism but officials had "reached no definitive judgment on the precise motivations of the killer."

"The attack that targeted a nightclub for homosexuals in Orlando, Florida and that left more than 100 dead and wounded was carried out by an Islamic State fighter," Amaq said.

Amaq, which is essentially the Islamic State's wire service, has issued other claims in the past including for the Brussels attack in March.

amaq isis orlando

Mateen called 911 during the rampage and reportedly swore allegiance to ISIS. He also name-dropped the Boston Marathon bombers, who constructed their pressure-cooker bombs from a how-to in al-Qaeda in the Arabian Peninsula's Inspire magazine.

The FBI first became aware of Mateen in 2013 and was interviewed twice after he made inflammatory comments to co-workers, the Bureau said today. They also investigated potential ties by Mateen to a suicide bomber yet closed the investigation after inconclusive findings.

The FBI said they're looking into domestic or international terror ties that Mateen had.