The Islamic State-inspired gunman who murdered 49 people at a gay nightclub in Florida had scouted Disney World resort in Orlando as a possible target before he carried out the mass shooting, it has been claimed.

Omar Mateen and his wife went to the theme park in April, with Mateen paying particular attention to the Disney Springs shopping area, which has lower level security than the theme parks, People magazine reported.

Security at US theme parks was being stepped up last night as a result.

It emerged on Monday that Mateen had been under investigation by the FBI for 10 months in 2013, when he was working as a security guard at a courthouse in Florida.

Colleagues alerted the authorities because they feared he was a terrorist after he said he wanted to “martyr” himself.

Thousands of people gathered in central Orlando last night night, holding candles and flowers in tribute to the victims of the Pulse nightclub killings.

The deadliest mass shooting in recent US history ended when police shot Mateen dead. The attack also left 53 people injured, five of them in a serious condition.