Sunday 2am EDT: An estimated 320 people are enjoying a night at the Pulse nightclub in Orlando Florida, when shooting suddenly starts.
By chance a uniformed police officer is working extra hours at the club as security but somehow the gunman was able to enter the club with two guns undetected.
The officer working security and two nearby officers engage in a gun battle with the gunman who then takes hostages inside the club.
2.09am EDT: A message posted on the Pulse Nightclub Facebook page warns patrons to “Everyone get out of pulse and keep running”.
Orlando Police officers direct family members away from a fatal shooting at Pulse Orlando nightclub Source: AAP
Over the next few hours police converge on the scene while the gunman continues to hold hostages inside.
About 2.21am EDT: Gunman calls 911 and pledges allegiance to IS.
3.58am EDT: Orlando Police take to social media to warn people of the situation and to stay away from the area.
5am EDT: SWAT team members drive an armoured vehicle into the doors of the club to smash their way in. A reported 30 patrons manage to escape afterwards.
Mina Justice shows a text she received from her son Eddie Justice at Pulse nightclub during a fatal shooting in Orlando, Florida. Source: AAP
5.05am EDT: Reports of an "explosion” at the club are revealed to be a controlled explosion by the Orlando Police who ask the people and media avoid inaccuracies in their reporting.
7.54am EDT: Orlando Police Chief John Mina reveals that multiple people have died and that the shooter was armed with a hand pistol and an assault rifle.
10.15am EDT: Authorities reveal the identity of the gunman as 29-year-old Omar Saddiqui Mateen and that the death toll stands at 50, with 53 more injured in the attack.
12 noon EDT: Florida Governor Rick Scott declares a state of emergency in Orange Country Florida.
1pm EDT: President Barack Obama denounces the attack as an act of hate and terror and denounces the shooter.
"In the face of hate and violence, we will love one another,” he said.
“We will not give in to fear or turn against each other, instead we will stand united as Americans to protect our people, to defend our nation, and take action against those who threaten us."
About 5pm EDT: City of Orlando starts releasing names.