The FBI said Omar Mateen had been radicalised by Islamist propaganda, but unlike the Paris attacks found no evidence that the shooting had been coordinated from abroad. (AFP File Photo)
The US gunman who launched the worst terror attack on American soil since 9/11 at a gay nightclub in Orlando was radicalised by Islamist propaganda, officials said, amid reports he was a club regular.
Lone gunman Omar Mateen killed 49 and wounded another 53 before he was killed when police stormed the Pulse, one of Orlando's most prominent gay venues, early Sunday.
The attack is reminiscent of the November 13 suicide attack on the Bataclan concert hall in Paris, where 90 people were massacred when jihadist gunmen opened fire on concertgoers.
A total of 130 people died across the French capital that night in a series of shootings and suicide bomb attacks.
The FBI said Mateen had been radicalised by Islamist propaganda, but unlike the Paris attacks found no evidence that the shooting had been coordinated from abroad.
The ISIS claimed that Mateen was acting as "one of the soldiers of the caliphate in America."
US investigators believe that Mateen was a "lone wolf" inspired by Islamist propaganda to carry out what President Barack Obama dubbed "an act of terror and an act of hate."
FBI chief James Comey said his agents found no evidence that the attack had been directed from outside the United States, "and we see no indication that he was part of any kind of network."
Agents are instead looking into the possible role of anti-gay bigotry.
The FBI was "highly confident" Mateen had been "radicalied" while consuming online propaganda, Comey said, adding that he claimed allegiance to ISIS leader Abu Bakr al-Baghdadi in a series of calls during the attack.