Taylor's father, who founded the club, is said to be in a non-life threatening condition in St Vincent's Hospital in Dublin.

An Garda Suíochána, the Irish police, told ESPN that one fatality occurred in the incident at 6.55am Tuesday morning after a gunman entered the club and opened fire just as a gym session was about to start.

The police later cordoned off a scene in the Ringsend area of Dublin after the discovery of a van believed to be connected to this shooting.

"A number of people had gathered to commence a gym session," said Garda Superintendent Pat Ward at scene of the shooting.

"There were about 15-20 people in the gym. They were just about to start their session when a gunman came in carrying a firearm, we believe it was a handgun, and he started opening fire. Three people received gunshot wounds.

"Unfortunately a 50-year-old man died at the scene and two others were injured. They were brought to hospital and are receiving treatment. We know that the gunman left the scene in a silver Volkswagen Caddy."

IBF and WBA female world champion Katie Taylor, who is currently training in the US ahead of her next fight, trained at the boxing club and claimed the 2012 Olympic gold medal and turned professional following the 2016 games.

In a statement released to ESPN, the Irish Athletic Boxing Association said: "The IABA are horrified that something like this could happen in the setting of a community sports club. Our thoughts are with those affected by this appalling event, their families and friends."