Update 9pm: Gardaí believe that at least four people were involved in today's shooting at the Regency Hotel in Dublin. 

Two were described at wearing police-style uniforms similar to a SWAT team uniform, including metal helmets. 

The men were armed with automatic weapons. 

Two others were carrying hand guns.  One was a man disguised as a woman and wearing an auburn wig and the other was stocky and wearing a beige cap. 

A van was later found burnt out at the Charlemont Estate in Marino. 

Gardaí confirmed that hree men were injured at the scene.  One of these men, aged in his 30s, was subsequently pronounced dead. 

Two other men were removed to The Mater and Beaumont hospitals with gunshot wounds. 

Chief Superintendent tonight said: "We know that there were a considerable number of people present in the Regency Hotel and we are appealing to them to provide any information they may have in relation to the shooting. 

"We are also appealing to anyone who was in the area of the Regency Hotel between 2-2.45pm, or anyone who was in the Charlemont Estate at that time is asked to contact Ballymun Garda Station on 01 666 4400 or the Garda Confidential line 1800 666 111". 

Earlier: A video has emerged of the moments gunmen opened fire at a weigh-in for a fight night in Dublin.  One man was shot dead. 

The video shows people scrambling for cover as shots ring out.  There is clear terror and confusion as people who had gathered for the event run to safety. 

A little girl's voice can be heard crying: 'Daddy help me…Daddy, what was that?' 

Credit: Storyful News

The attack happened while a boxing tournament weigh-in was going on at the Regency Hotel on Swords Road, around three kilometres north of the city centre. 

There men aged in their 20s or 30s were injured in the shooting. 

Witness Mel Christle, president of the Boxing Union of Ireland, was standing on a podium where the last of the boxers weighing in had just stood down when he heard gunfire erupting outside the room. 

“There was a horrific cracking noise, in front of me, out of the banquet room - it was a place called the Regency Suite,” he said. 

“There was an incredible noise out there, and that is where I saw a body, a corpse, lying literally at the edge of the reception desk.  So I’m sure he (the victim) was trapped – he was riddled.” 

Mr Christle said one of the gunmen was dressed up as a woman and aged in his early 20s. 

The boxing chief was adamant the attackers were not targeting the boxers gathered for the weigh-in, but other individuals who were hit in the hotel reception. 

He said there was panic as some people dived for cover when they realised what was happening. 

“I actually saw the sheer fear that will live with them for a long, long time,” he said of those who witnessed the shooting. 

“It actually touched me, how afraid – I’m sure adults were afraid, but my God, the children couldn’t believe what was going on.” 

The Taoiseach Enda Kenny has said he hoped those responsible for the gangland-style shooting were brought to justice, and he wished gardaí well with their "full-scale murder hunt and investigation". 

Update 5.15pm: The fight night which had been due to take place in Tallaght's National Arena tomorrow has been cancelled after a fatal shooting at a weight-in for the event. 

Tickets.ie has confirmed the cancellation. 

The event included a WBO European lightweight title fight between Jamie Kavanagh and Antonio Jao Bento. 

Box Nation, the television channel scheduled to broadcast the fight, said in a message on Twitter that the show had been cancelled due to the shooting. 

“Following today’s incident at the Dublin weigh in, tomorrow’s show from the National Stadium has been cancelled,” the post said. 

The bout was being promoted by Frank Warren and MGM Promotions, according to MGM, a Marbella-based gym run by Birmingham-born Irish boxer Matthew Macklin. 

Two years ago, former European light-middleweight boxing champion Jamie Moore was shot twice in the legs in Marbella, where he was training Macklin at the time. 

Update 4.50pm: A man who travelled to attend a planned fight in Dublin this weekend, has spoken of the moments at a weigh-in today when gunmen opened fire, killing one and injuring two others. 

The witness said: "I just saw a gun, an AK47.  He started shooting...and then it was 'Run, run, just run!' 

"We just came for the fight, and now we go home." 

Update 3.40pm: Gardaí have confirmed that three men, all in their 20s and 30s, were found injured at the scene of a shooting in a Dublin hotel this afternoon, and that one subsequently died. 

The two others were taken to The Mater and Beaumont hospitals with possible gunshot wounds (not believed to be life-threatening) after the shootings at a weigh-in for a boxing match in the Regency Hotel in Swords, on the northside of the city. 

The scene is sealed off for a technical examination. 

Gardaí have appealed for anyone in the area of the Regency Airport Hotel or who may have information, to contact them at Ballymun garda station on 01 6664400. 

Initial reports suggested the shooting was gang-related, and that eyewitnesses said at least one of the men was carrying what looked like an AK47. 

Update 3.30pm: One man is believed to have been killed at a shooting in Dublin hotel, where a weigh-in was taking place for a boxing match taking place tomorrow night at the National Arena in Tallaght.  The weigh-in was scheduled for 2pm. 

One person has been killed and two injured in a #shooting at the Regency Hotel in Dublin https://t.co/DrASguW4M3 https://t.co/J1QsBmWr3U — SkyNews (@SkyNews) February 5, 2016

Earlier:

Two people are reported to have been seriously injured after shots were fired at a boxing weigh-in in Dublin. 

The weigh-in at the Regency Airport Hotel on the Swords Road, between Collins Avenue and Griffith Ave, was interrupted at about 2.30pm when three men dressed in uniforms entered the foyer of the hotel carrying guns. 

They fired a number of shots.  There are unconfirmed reports that two men were seriously hurt.  A further report that one man had been killed cannot currently be confirmed. 

Emergency services outside the Regency Hotel in Dublin.  Picture: PA

Initial reports suggested the shooting was gang-related, and that eyewitnesses said at least one of the men was carrying what looked like an AK47. 

Dublin Fire Brigade and paramedics are at the scene.  Gardaí confirmed they were also attending the scene of an incident, but that they had no further details at this stage.