A BC Ambulance spokesman confirmed that four people were transported to hospital after the incident, which occurred during a longshoreman induction meeting. Some of the victims sustained life-threatening injuries, officials said.
Six ambulances responded to the scene and there were about 100 people inside the Riverside Banquet Hall when several shots rang out just after 9 p.m. PT, police said.
Three of the victims were taken to Vancouver General, and one was transported to Richmond General.
Reports showed pictures of a bloody scene and the injured being attended by paramedics.
Police said it doesn't appear the incident is linked to gang violence.
Mark Gordienko, president of the Longshoreman's Union, said he was stunned by the violence that unfolded during the meeting, and said he was sending his best wishes to the families of the victims involved.
The hall is located in the 14500-block of River Road in the city, just south of Vancouver.
The other occupants of the building were transported by bus to Richmond RCMP so they could be questioned as potential witnesses.