Gunman who killed 50 in worst US mass shooting was known to the authorities
A gunman who massacred 50 people in a mass shooting at a gay nightclub was known to US authorities, it has been revealed.
Omar Mateen was armed with a powerful assault-type rifle and handgun when he sprayed revellers with bullets at the popular venue, Pulse, in Orlando, Florida.
The FBI said the 29-year-old killer born in New York was an American citizen who legally purchased two firearms within the last week.
Despite being aware of Mateen since 2013, following inflammatory comments made to co-workers and over ties to an American suicide bomber in 2014, he was not under surveillance.
Authorities deemed his link to the bomber to be minimal so did not constitute a threat, and after interviews and an investigation dropped the probe into his comments.
It has been revealed that 911 calls involving the shooter from Port St Lucie, Florida and featuring conversations about the Islamic State before the massacre, have now become federal evidence.
US president Barack Obama called the killings at the gay-friendly establishment an "act of terror" and an "act of hate" and said they are being investigated as terrorism.
More than 300 people were inside the building at the time of the attack, which has now become the worst mass shooting in American history - 53 people have also been taken to hospital.
President Obama praised the emergency service response and described the gunman as a person "filled with hatred".
He said the massacre is a reminder of how easy it is for someone to access a weapon like a gun, allowing them to go on and shoot other people.
"We have to decide if that is the type of country we want to be. To actively to do nothing is a decision as well," Mr Obama added.
The first names of the victims have now been released by the police - Edward Sotomayor Jr, Stanley Almodovar III, Luis Omar Ocasio-Capo and Juan Ramon Guerrero are among the dead.
Mir Seddique, the father of the shooter, told NBC News that he thinks a recent experience in which his son saw two men kissing might be related to the shooting.
He apologised for the whole incident, said he was not aware of the actions of his security guard son and claimed "this had nothing to do with religion".
The killer, who also held hostages in a three-hour stand-off, later died in a gunfight with Swat officers in the Florida city. He exchanged gunfire with 14 officers at the club.
Mr Obama has also ordered flags at the White House and federal buildings to be flown at half-mast as a mark of respect for the victims.
And in the aftermath of the massacre, police departments across the US increased patrols around popular gay-friendly locations and venues.
Orlando mayor, Buddy Dyer, described the scene saying there was "blood everywhere".
Political leaders from around the world have since condemned the attack and offered their condolences to the victims.
Afghanistan's president Ashraf Ghani said "targeting civilians is not justifiable under any circumstances whatsoever", while Prime Minister David Cameron said he was "horrified" by the shooting.
French president Francois Hollande said he "expresses the full support of France and the French with America's authorities and its people in this difficult time".
And Buckingham Palace said the Queen had sent a personal message to Mr Obama on Sunday night, saying: "Prince Philip and I have been shocked by the events in Orlando.
"Our thoughts and prayers are with all those who have been affected."