The suspected gunman in the shooting at a gay nightclub is believed to be a US citizen of Afghan descent, US television networks reported, even as his father said the attack was not motivated by religion.
CBS News identified the suspect as 29-year-old Omar Mateen, who was born to Afghan parents in 1986 and lives in Port St Lucie, Florida.
He called 911 just before the Orlando club shooting and swore allegiance to the Islamic State terror group, NBC News reported, quoting multiple unnamed law enforcement officials.
Soon after, Islamic State’s Amaq news agency claimed the group was responsible for the shooting that killed at least 50 people at the Florida nightclub. But Senator Bill Nelson said the claim was not yet confirmed.
US officials said they had no immediate evidence of any direct connection between the worst mass shooting in US history and Islamic State or any other foreign extremist group, Reuters reported.
But, a top Democrat on a congressional intelligence committee said local law enforcement believed the suspect in the deadly Orlando shooting had pledged allegiance to the Islamic State, which claims to be behind the Paris and Brussels attacks.
“The fact that this shooting took place during Ramadan and that ISIS leadership in Raqqa has been urging attacks during this time, that the target was an LGBT night club during Pride, and - if accurate - that according to local law enforcement the shooter declared his allegiance to ISIS, indicates an ISIS-inspired act of terrorism,” representative Adam Schiff said in a statement.
Florida governor Rick Scott too said the overnight shooting was “clearly an act of terror”.
“For somebody to go in there and be an active shooter and take that number (of lives) ... is clearly an act of terror,” the Republican told a news conference.
The father of the suspected gunman said he believed his son was motivated by hatred of gays -- not by his Muslim religion.
“This had nothing to do with religion,” Mir Seddique told NBC News.
He said his son recently lashed out in his presence after witnessing a gay couple embracing in downtown Miami, and suggested the incident may have triggered the atrocity.
“He saw two men kissing each other in front of his wife and kid and he got very angry,” Seddique told the network.
Fox News reported that he was known to the Federal Bureau of Investigation, but the reason was not immediately clear.
A Twitter account associated with Islamic State militant group posted a photo purported to be of Mateen.
“The man who carried out the Florida nightclub attack which killed 50 people and injured dozens,” the caption accompanying the photo read.
It was not possible to verify whether the picture was in fact of Mateen. Other Twitter accounts linked to Islamist militancy also carried photos of the same individual, and Islamic State supporters posted messages of praise for the attack.