The Islamic state known as ISIS has claimed responsibility for the deadly attacks early Sunday morning in Orlando, Florida, that left 50 dead and 53 injured.
The report comes from ISIS-affiliated news outlet Amaq Agency.
The lone assailant, a 29-year-old American-born man named Omar Mateen, called 911 during the Orlando attacks, pledging his allegiance to ISIS, officials said.
“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, according to Reuters.
While at the scene, Mateen also mentioned the Tsarnaev brothers, who carried out the deadly 2013 bombings at the Boston Marathon.
It is unclear if Mateen had been in contact with any individuals from the Islamic State or was acting as a lone wolf in support of the group’s radical ideology.
The Orlando massacre is considered the worst mass shooting in U.S. history and the biggest terror attack since the tragic events on Sept. 11, 2001.
Mateen was born in New York City to Afghan parents, according to NBC News. He worked as a private security guard and lived in Port St. Lucie, Florida, which lies 125 miles south of Orlando where the massacre takes place.