The Islamic State’s radio channel has called the Orlando mass killer “one of the soldiers of the caliphate in America”.

Al-Bayan Radio, a media outlet for the IS extremist group, hailed the attack that left 50 people dead, saying it targeted a gathering of Christians and gays and that it is the worst attack on US soil since the September 11, 2001, terrorist attacks.

Authorities say Omar Mateen opened fire with an AR-15 rifle at a gay nightclub early on Sunday before being killed in a shootout with police.

Another 53 people were wounded in the shooting.

As yet, IS has not officially claimed responsibility for the Orlando attack.