Death toll expected to rise among victims of Orlando massacre
* Survivors describe chaos
* Mateen's former colleague complained about his bigotry
* Deadliest mass shooting in US history
* At least 53 wounded in rampage at 'Pulse' club
Families of the victims of the Orlando gay club massacre face an agonising wait as to whether their loved ones are missing, injured or dead.
Gunman Omar Mateen killed 50 men and women and injured 53 at Pulse nightclub in Orlando early Sunday morning in the worst mass shooting in American history.
39 bodies were recovered at the scene and 11 more died in hospital. The majority of those injured were taken to Orlando Regional Medical Centre where trauma surgeon Dr Mike Cheatham said: “I think we will see the death toll rise."
More victims have been identified as officials are still at the scene as bodies are still being removed.
Edward Sotmayor Jr (34), Stanley Almodovar III (23), Juan Ramon Guerrero (22), Eric Ivan Ortiz-Rivera (36), Luis Omar Ocasio-Capo (20), Luis S. Vielma (22), Peter O. Gonzalez-Cruz (22), Kimberly Morris (37), Eddie Jamoldroy Justice (30) and Darryl Roman Burt II (29) are among those confirmed dead.
An eyewitness states the shooter, who was known to the FBI, was sitting at the bar having a drink before opening fire and "picking off" clubgoers one by one at 2am on Sunday morning.
Survivor Christopher Hansen told NBC News he originally thought the gunshots was part of the music, then saw people fall to the ground.
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"I just saw bodies going down. Bang, bang, bang," he said.
"People stomped on me. ... I was zigzagging just in case, because you could still hear the bullets going off. I was terrified. I was in shock."
"I had just seen the movie The Conjuring 2...to go from a horror movie to a real horror, it's just shocking."
Vigils were held around the world on Sunday night showing unity with Florida, while others have urged for firmer gun control laws in the US.
Omar Mateen was previously on the FBI's terrorist watch list and was questioned by agents in 2013 and 2014, but was eventually removed and officials closed the investigation.
He called 911 pledging allegiance to ISIS, who have since claimed responsibility for the attack, before killing 50 and injuring dozens. Law enforcement officials have described it as the worst domestic terror attack since 9/11.
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He purchased two guns - a .223 caliber AR type rifle and a 9mm semiautomatic pistol - in the days before the attack.
A former colleague of Mateen's - 44-year-old Daniel Gilroy - complained about him at their previous place of employment for making slurs against African Americans, gay people and women.
"I complained multiple times that he was dangerous, that he didn't like blacks, women, lesbians and Jews," Gilroy told The Times on Sunday.
"You meet bigots. But he was above and beyond. He was always angry, sweating, just angry at the world."
His ex-wife described him as mentally unstable and said he physically abused her during their marriage.