The shooter also claimed he had a vehicle with "some bombs" outside
The man who killed 49 people in a Florida nightclub told a 911 operator: "I'm in Orlando and I did the shootings."
The FBI revealed that Omar Mateen spoke in Arabic when he talked to police call handlers after the attack began.
FBI records show the incident started with reports of multiple shots fired at the Pulse nightclub at 2.02am on Sunday, June 12th.
Then at 2:04am, officers arrived on the scene - gaining entry to the club four minutes later and engaging with the shooter.
Then at 2:35am, the shooter, Omar Mateen, contacted a 911 operator from inside the club.
The call, between an Orlando Police Dispatcher (OD) and Mateen (OM), lasted approximately 50 seconds.
OD: Emergency 911, this is being recorded.
OM: In the name of God the Merciful, the beneficial [in Arabic]
OM: Praise be to God, and prayers as well as peace be upon the prophet of God [in Arabic]. I let you know, I’m in Orlando and I did the shootings.
OD: What’s your name?
OM: My name is I pledge of allegiance to [omitted].
OD: Ok, What’s your name?
OM: I pledge allegiance to [omitted] may God protect him [in Arabic], on behalf of [omitted].
OD: Alright, where are you at?
OM: In Orlando.
OD: Where in Orlando?
[End of call.]
Shortly after that, Mateen engaged in three phone calls with the police negotiation team.
In these calls, Mateen - who identified himself as an Islamic soldier - told the negotiator that he was the person who pledged his allegiance to [omitted], and to tell America to stop bombing Syria and Iraq.
He claimed that is why he was "out here right now."
When the crisis negotiator asked the shooter what he had done, the shooter stated: "No, you already know what I did."
"There is some vehicle outside that has some bombs, just to let you know," Mateen continued.
"You people are gonna get it, and I'm gonna ignite it if they try to do anything stupid."
Later in the call with the negotiator, Mateen stated that he had a vest, and further described it as the kind they "used in France."
The shooter later said: "In the next few days, you're going to see more of this type of action going on."
He then hung up and multiple attempts to get in touch with him were unsuccessful.
Orlando police chief John Mina said the timeline released by authorities showed that officers were on the scene within minutes of when shooting began and quickly exchanged gunfire.
"That was important because it caused him to retreat, stop shooting and barricade himself in the bathroom with hostages," he said.
"After that initial exchange of gunfire, there was no other gunfire until the actual hostage rescue operation took place."
"During that (three hours before the rescue), our officers were in and out of that club, rescuing people."
FBI assistant special agent in charge of the operation in Orlando, Ron Harper, said that police were not releasing the audio of the conversations - but wanted the public to know his manner while talking to dispatchers.
"He did so in a chilling, calm and deliberate manner," he said.
But he added: "To expose (the audio) now would be excruciatingly painful to exploit (the victims) in this way."
"As you will see from the transcripts, the killer of 49 identified himself as an Islamic soldier who pledged allegiance to a terrorist organisation which was bent on killing Americans."
"He does not represent the religion of Islam but a perverted view which, based on what we know today, was inspired by extremist killers."
"We currently have no evidence that he was directed by a foreign terrorist group."