Police officers at the site of the shooting incident in Orlando. (Photo: IANS)
At least 50 people were killed and other 53 people were injured when a gunman opened fire early on Sunday in a gay nightclub in Orlando, Florida, where a state of emergency has been declared.
The gunman, named by officials as Omar Mateen, 29, was killed by a SWAT team after he took hostages at Pulse, a popular gay night club.
It is believed that the suspect, who was a US citizen from the Florida town of Port St Lucie and was of Afghan descent, was not on a terrorism watch list, although he was being investigated for an unrelated criminal act, BBC reported.
Officials said the killings were likely to be ideologically motivated, though there was no information that the gunman was associated with a particular group.
He was armed with an assault rifle, a handgun and an unspecified "device", said officials.
"It appears he was organised and well-prepared," Orlando Police Chief John Mina said.
The shooter's father told NBC News: "This has nothing to do with religion."
Mir Seddique said Omar Mateen had been angry when he saw two men kissing in Miami recently.
"We are saying we are apologising for the whole incident. We weren't aware of any action he is taking. We are in shock like the whole country," Seddique told NBC News .
US President Barack Obama was briefed on the mass shooting, which police described as an act of terrorism.
Our thoughts and prayers are with the families and loved ones of the victims. The President asked to receive regular updates as the FBI, and other federal officials, work with the Orlando Police to gather more information," said a statement by Barack Obama's press secretary.