Orlando Pulse massacre killer Muslim Mateen 'was a US-born extremist who had been investigated' - Northern Ireland joins in worldwide tributes to 49 victims
The gunman who killed 49 people in an attack on a gay nightclub in Orlando was a "homegrown extremist" who supported different Islamist groups, said the FBI and the White House.
Counter-terrorism authorities have been investigating Omar Mateen's background and defended their handling of the gunman after it was revealed they'd had previous contact with him.
US-born Muslim Mateen (29), opened fire at Pulse Orlando club early on Sunday. He was killed in a gun battle with a SWAT team after police used explosives and a small armoured vehicle to punch a hole in a wall and allow dozens of revellers to escape.
Orlando's Mayor Buddy Dyer said: "We will not be defined by the act of a cowardly hater."
FBI director James Comey said Mateen had "strong indications of radicalisation" and was probably inspired by foreign terrorist organisations.
He said Mateen called the 911 emergency number around the time of the attack and pledged loyalty to Islamic State as well as solidarity with the Tsarnaev brothers who carried out the Boston Marathon bombing.
Mateen had also expressed support in recent years for both al Qaida and its enemy Hezbollah, Mr Comey said. The FBI probed Mateen for 10 months beginning in May 2013 after he was said to have made inflammatory remarks supporting terrorists.
Mr Comey said investigators introduced him to confidential sources, followed him and reviewed some of his communications, but Mateen claimed he made the remarks in anger because co-workers were teasing and discriminating against him because he was Muslim. The investigation was closed.
Meanwhile, a steady stream of people filed through a makeshift memorial about a mile from the nightclub. It consisted of dozens of bouquets and candles.
Mateen's intentions seemed to become murkier when his Afghan immigrant father suggested anti-gay hatred was another possible motive. The father said his son got angry a few months ago when he saw two men kissing in Miami. Mateen's ex-wife attributed the violence to mental illness, saying he was abusive to her.
Mr Obama said investigators are still looking into the killer's motivations and considering all possibilities, noting that Muslim extremist groups like Islamic State are known to target gays.
The Islamic State's radio called Mateen "one of the soldiers of the caliphate in America".
Mateen's father, Seddique Mir Mateen, told reporters that the massacre was "the act of a terrorist", and added: "I apologise for what my son did. I am as sad and mad as you guys are."
Asked whether he missed his son, he said: "I don't miss anything about him. What he did was against humanity."
Thirty-nine of the dead were killed at the club, and the others died at hospitals, the mayor said. At least 53 people are being treated in hospital. Mateen exchanged gunfire with 14 police officers at the club and took hostages at one point. In addition to the assault rifle and handgun, he had a weapon in his vehicle.