Omar Mateen: Orlando gay night club shooter was Isis fighter, according to Amaq News Agency

Omar Mateen reportedly called 911 and pledged allegiance to ISIS

Police outside the Pulse nightclub in Orlando, scene of the worst mass shooting in US history (GETTY)

The shooter who killed at least 50 people in a LGBT nightclub in Florida called emergency services and swore allegiance to the head of ISIS, according to police.

Omar Mateen, who reportedly called 911 before the attack, shot down at least 50 people at the Pulse nightclub.

Islamic State, which is strongly anti-LGBT, has allegedly claimed responsibility for the shooting, according to ISIS-affiliated news agency Amaq, although an official claim from ISIS has been disputed.

President Barack Obama said the shooter was a man “filled with hate” and called the incident the worst shooting in US history.

The 29-year-old, who was born in New York, was equipped with a handgun and an assault rifle.

The Council on American-Islamic Relations, the largest advocacy group for Muslims in the US, has asked the Muslim community to donate blood to those injured in the attack.

Rasha Mubarak, the Florida chapter’s Orlando regional co-ordinator, said: “We condemn this monstrous attack and offer our heartfelt condolences to the families and loved ones of all those killed or injured. The Muslim community joins our fellow Americans in repudiating anyone or any group that would claim to justify or excuse such an appalling act of violence.”

Mateen was also accused of beating his ex-wife regularly before the attack.