UPDATE: The gunman responsible for the deadliest mass shooting in modern U.S. history paused from the slaughter inside the Pulse nightclub to call the Orlando police and confess to his crime.

"Praise be to God, and prayers as well as peace be upon the prophet of God," Omar Mateen said in a transcript of his call to police dispatchers that the FBI released on Monday. "I let you know, I'm in Orlando and I did the shootings."

That chilling admission was among the excerpts of the 911 calls from June 12 the feds released along with a timeline of the terror at the gay nightclub that left 49 dead and more than 50 people wounded.

Mateen also warned that there was vehicle packed with explosives outside the nightclub that he would "ignite" if police tried "to do anything stupid." No explosives were found.

In its document release, the FBI made a point of not identifying Mateen by name and did not identify the radical Islamic group to which he swore allegiance.

"We're not going to propagate violent rhetoric," said FBI Assistant Special Agent in Charge Ron Hopper. "There's no purpose in doing that."

Hopper said they have "no evidence that he was directed by a foreign terrorist group, but was radicalized domestically." He said there are a "myriad of things" that could have motivated the attack.

House Speaker Paul Ryan, R-WI, called the FBI's decision to redact the transcript of Mateen's call to the dispatchers "preposterous."

"We know the shooter was a radical Islamist extremist inspired by ISIS," Ryan said in a statement. "We also know he intentionally targeted the LGBT community. The administration should release the full, unredacted transcript so the public is clear-eyed about who did this, and why."

The FBI also said that "out of respect for the victims" it would not releasing audio of Mateen's call or "audio or transcripts of the calls made by victims at the Pulse nightclub during the incident."

Orlando Police Department Chief John Mina said his officers were at the nightclub "within minutes and engaged the suspect in gunfire."

"That engagement and that initial entry caused him to retreat, stop shooting and barricade himself in the bathroom with hostages," Mina said. "There was no other gunfire until the hostage rescue took place."

Mina said he also wanted to clear up "misconceptions that we didn't do anything for three hours" before the SWAT team moved in and went after the 29-year-old shooter.

"We let our negotiators take over in an effort to save lives while out SWAT team set up," Mina said.

Asked if any of the victims may have been accidentally shot by police, Mina said "that's all part of the investigation."

"But here's what I can tell you," he said. "Those killings are on the suspect and on the suspect alone. Our officers acted heroically."

Among the new revelations contained in the transcripts was that at 4:21 a.m., on the night of the mayhem, Orlando police officers pulled an air conditioning unit out of a Pulse dressing room window, enabling at least eight people trapped inside to escape.

Meanwhile, NBC News has learned that the Orange County Medical Examiner's Office has released the body of Mateen.

Contacted by NBC, the suspect's father, Siddique Mateen, said he was not aware of any plans to have his son's body transferred to him. A source close to Mateen's widow Noor Salman said she was asked if she would take her husband's body and she said no.

The transcript and timeline is below:

Orlando Police Dispatcher (OD): Emergency 911, this is being recorded.

Shooter (OM): In the name of God the Merciful, the beneficial [in Arabic]

OD: What?

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, the shooter engaged in three conversations with the Orlando Police Department's Crisis Negotiation Team.

2:48 a.m.: First crisis negotiation call occurred lasting approximately nine minutes.

3:03 a.m.: Second crisis negotiation call occurred lasting approximately 16 minutes.

3:24 a.m.: Third crisis negotiation call occurred lasting approximately three minutes.

Here's a description of what he said:

In these calls, the shooter, who identified himself as an Islamic soldier, told the crisis negotiator that he was the person who pledged his allegiance to [omitted], and told the negotiator to tell America to stop bombing Syria and Iraq and 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." The shooter continued, stating, "There is some vehicle outside that has some bombs, just to let you know. 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 crisis negotiator, the shooter stated that he had a vest, and further described it as the kind they "used in France." The shooter later stated, "In the next few days, you're going to see more of this type of action going on." The shooter hung up and multiple attempts to get in touch with him were unsuccessful.

PREVIOUS STORY: The FBI will release a partial transcript on Monday of Omar Mateen's phone calls with police negotiators during a mass shooting in Orlando last week that left 49 dead, Attorney General Loretta Lynch said Sunday.

On "Meet the Press," Lynch said that during the calls, a police negotiating team was trying to determine who Mateen was, "where he was, and why he was doing this, all while the rescue operations were continuing."

Authorities have previously said that during three conversations with a 911 dispatcher, Mateen pledged allegiance to ISIS' leader, Abu Bakr al-Baghdadi.

Mateen allegedly also said he admired the brothers who bombed the 2013 Boston Marathon, describing them as his "homeboys," as well as Moner Mohammad Abu-Salha, a 22-year-old Palestinian American from the same town as Mateen who carried out a suicide attack in Syria.

Abu-Salha carried out the bombing on behalf of Al-Nusra Front, a terrorist rival of ISIS.

When asked what was being left out of the transcript, Lynch responded by saying that it will not help to "further proclaim this individual's pledges of allegiance to terrorist groups and further his propaganda."

The news comes ahead of a planned Sunday vigil in Orlando, which is expected to draw as many as 20,000 people.