The suspected Islamic extremist, who killed about 50 people after taking party-goers hostage inside a gay club in Orlando, has been identified.
Law enforcement sources have identified the shooter, who was wielding an assault rifle and a handgun, as US citizen Omar Mateen, from Port St. Lucie in Florida.
The gunman, who was born to Afghan parents, was carrying a suspicious device, possibly a suicide vest, when he opened fire on the dance floor inside Pulse in the early hours of the morning.
Orlando Police Chief John Mina said authorities have not determined the exact number of people killed, but that 'approximately 50' have died. Another 42 people were taken to hospital.
An FBI spokesman said the mass shooting is being investigated as an act of terrorism, adding that they are looking into whether this was an act of domestic or international terror, and if the shooter was a lone wolf.
Police said the gunman, who was shot dead by officers, was believed to be in his 20s, while the FBI believe he may have 'leanings to radical Islamic terrorism'.
The killings took place less than four miles from where The Voice singer and YouTube star Christina Grimmie, 22, was shot dead at The Plaza Live in Orlando on Friday.
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