Four gunmen, carrying AK-47s and handguns, opened fire in the Regency Hotel in Dublin on Friday afternoon, killing one and injuring two others. About 100 people, including members of the Christy Kinahan crime syndicate, were in the hotel attending a weigh-in for a boxing event planned on Saturday.

Witnesses say three of the gunmen were dressed as gardaí; a fourth was dressed as a woman in a long blonde wig and a grey dress. The gunmen entered the hotel at about 2.30 pm and started shooting at a group of people attending the weigh-in. The Irish Times reports that police believe the gunmen specifically targeted this group and that the three men who were wounded were among those present for the weigh-in. 

David Byrne, 34, a key Dublin-based member of the Christy Kinahan cartel, died at the scene. Sean McGovern, 30, is in serious condition at Beaumont Hospital after being shot in the stomach, while Aaron Bolger, 25, was being treated after he was shot in the thigh.

The Irish Independent reports the shooting is believed to be linked to the murder of criminal Gary Hutch, a nephew of Gerry ‘The Monk’ Hutch, in southern Spain four months ago.

Taoiseach Enda Kenny called the shooting "an extreme case.”

"There is a full-scale murder hunt going on here," said Mr Kenny. "Clearly, the interpretation here is that this is the work of rival criminal gangs in the Dublin area."

Party colleague Richard Bruton called it "a new low.” The Regency Hotel is on the edge of his constituency. 

"I think it's very disturbing. I mean the Regency Hotel is a family-run hotel as you know - it's a place that many, many people go for a quiet evening or to events," he said.

"It is really very disturbing to see that level of wanton violence, the disregard for other people who were there.

"It's a new low I think in that sort of criminal activity."

About 20 people were in the foyer and bar area of the hotel when one of the gunmen jumped onto the reception desk and pointed his gun at a BBC sports journalist, who begged not to be shot.

"They fired into the bar and could have hit anyone. They could have turned on anyone," said hotel manager John Glynn, who said he saw one man shot dead in the reception area of the hotel. "They could have fired on me or any of the staff or guests."

Journalist Kevin McAnena was in the foyer of the hotel when the gunmen entered. 

"Most other people had run out and I almost kind of froze," the BBC Radio Foyle sports reporter told RTÉ. "One other guy ran across the lobby and one of the guys with the guns shot him in the lower leg and he went down. He was possibly six feet from me. That's the guy who has now died. At that point I jumped over the receptionist desk and got on the ground."

"I started shouting 'don't shoot, don't shoot' because I could hear more gunfire from the other side."

At the same time, there was a shoot-out in the function room where the weigh-in was being held.

Mel Christle, president of the Boxing Union of Ireland, said the weigh-in had just finished when the shooting started.

"Everyone including quite young children - aged as young as five years old - and their relatives were there," he said.

He said: "One person who had been shot in his leg at the very back of the hall."

"When I was leaving about 20 minutes later, I could see a corpse slumped against the reception desk. His face was completely distorted, is what I can say about it."

Another witness said "all hell broke loose" when a man came in and fired three shots in the air.

"There [was] glass breaking, chairs toppling over. It was pure chaos as people tried to run," he said. 

He said there were other men in there with guns, and they were picking their targets.

"Other men were armed but we didn't know if [they] were with the men pretending to be gardaí or shooting at them."

Video footage of the shooting showed dozens of people fleeing in fear. A chid can be heard screaming: “Daddy, help me… what was that?”

The gunmen fled the scene on foot and were driven away in a van waiting outside. The van was later found burnt out at the Charlemont Estate in Marino.

A man-hunt is currently underway for the shooters. Chief Superintendent Barry O'Brien, from Ballymun, said they were looking for four men, including some who wore "SWAT-type police uniforms with metal helmets, the likes of which you would see in a crime drama.”

The weigh-in taking place at the time of the shooting was for the ‘Clash of the Clans’ promotion in the National Stadium, Dublin, on Saturday night.

According to a tweet on Friday afternoon from Box Nation: “following today’s incident at the Dublin weigh-in, tomorrow’s show from the National Stadium has been cancelled.”

This photo shows two of the gunmen entering the hotel.Irish Independent