Orlando shooting survivor describes gunman Omar Mateen laughing as he shot victims trapped in bathroom

'I just heard him laugh, then he disappeared into the other room and kept going'

Police blew holes in the bathroom wall to free hostages (Getty Images)

A survivor of the massacre inside an Orlando nightclub has described the gunman laughing as he shot victims trapped in a toilet cubicle.

Norman Casiano, 26, was shot four times but has since been discharged from hospital in Florida.

He had gone to Pulse on Saturday night to celebrate a friend’s birthday and was among 300 people inside when Omar Mateen opened fire.

“I heard the first two gunshots, I automatically just threw myself down to a floor,” he told Local 10 News.

Mr Casiano crawled into a nearby bathroom and into a disabled cubicle where around a dozen people were already cowering, closing the door to in an effort to hide themselves.

He described people weeping and holding each other as they heard the gunshots getting closer, before a man stumbled into the bathroom and collapsed on the floor.

“He’s bleeding everywhere and he’s begging to come inside the stall, we’re trying to get him in but he wouldn’t fit underneath and we couldn’t open the door,” Mr Casiano said.

“Five seconds pass by and the assailant came in and shot him one last time.”

Struggling to hold back tears, he said he watched the man die on the floor as victims begged Mateen not to kill them.

“The scary part was that he didn't say anything, and what's scarier than that when he shot the boy that was already shot, he laughed and as he’s laughing that’s when he fires through the whole front of the stall,” Mr Casiano said.

“We’re yelling at him, being like ‘please, please don’t do this, you don’t want to do this, just spare us, we didn’t see you, we can’t tell anybody’, I guess that enticed him more.

"He put his gun over the stall and willy-nilly fired and that’s when I got (shot on) this side…I just heard him laugh, then he disappeared into the other room and kept going.”

Mr Casiano had to climb over the bodies of Mateen’s victims to get out of the bathroom and be taken to safety by police.

Mateen was trapped in another bathroom after officers stormed the club, holding hostages for three hours until Swat teams blew a hole in the wall and shot the gunman dead in the ensuring battle.

The victims, aged between 18 and 49, included a young couple hoping to get married and a much-loved employee at the Universal theme park.

One of those killed, Amanda Alvear, was filming a Snapchat video when the massacre started, showing her dancing with friends before shots rang out.

At least 49 people were killed and 53 injured in the attack, which was the worst mass shooting in US history and the deadliest terror attack on American soil since 9/11.

Old Compton Street fell silent at 7pm as a sign of respect for the partygoers killed on Sunday morning (Giles Terera)

Thousands of people gathered in vigils across the US and around the world to remember the victims on Monday night.

Isis claimed responsibility for the shooting, calling the gunman “a soldier of the Caliphate”, but there was no indication that the terrorist group had contact with the gunman or directed the atrocity.

“It does appear that at the last minute he announced allegiance to Isil (Isis) but there is no evidence so far that he was in fact directed by Isil or that it was part of a larger plot,” Barack Obama said.

The FBI's had investigated Mateen for 10 months and interviewed him twice after colleagues raised concerns over radicalisation in 2013 but found no evidence of a crime or connection with a militant group.

There have been conflicting reports of motivation for his attack, with his former wife saying he was mentally ill and his father telling media he had been angered by seeing two men kiss, while acquaintances claim Mateen was himself gay but felt unable to be open about his sexuality