Islamic State claims responsibility for Orlando nightclub shooting

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.

The suspect in the Orlando attack was identified as Omar Mateen of Port St. Lucie, Florida.

The gunman's father recalled to NBC News that his son recently got angry when he saw two men kissing in Miami and said that might be related to the assault.

The co-owner of Pulse, the Orlando gay nightclub that became the scene of the worst mass shooting in U.S. history on Sunday, founded the club to honor her brother who died of AIDS and to support the lesbian, gay, bisexual and transgender community.

Barbara Poma, whose brother died in 1991, opened Pulse in 2004 with business partner Ron Legler. The venue promoted gay rights and put on events supporting happenings in the gay community, ranging from Come Out with Pride to Gay Games, according to the club's website.

Pulse's patrons and others in Orlando's gay community were reeling on Sunday after a gunman killed 50 people and wounded 53 others overnight in what police said was a targeted, well-planned attack.