A shooting in St. Paul, Alta., has left one gunman dead and three RCMP members wounded.

Chief Supt. Randy McInnis says two of the officers were sent to Edmonton by air ambulance while the third remained in St. Paul. The gunman was reportedly killed in the confrontation.

There are no RCMP fatalities expected. It is unknown at this time if any civilians are wounded.

It just went insane downtown. Lots of gunfire. - Mike Vanderhoek, witness of the St. Paul shooting

McInnis described the situation as "mayhem" and said they are still in the process of "trying to get things under control."

The Alberta Serious Incident Response Team (ASIRT) is investigating the incident.

Mike Vanderhoek was downtown around 6 p.m. when he heard what sounded like two rifle shots in the west side of downtown.

"I was just driving around town, and all of a sudden I see a police cruiser whip in through the emergency door where an ambulance would park," Vanderhoek told CBC News. "And it just went insane downtown. Lots of gunfire."

He described the scene as "very hectic."

"Downtown was very, very busy," Vanderhoek said. "There were people hiding behind vans, ducking in front of cars. I don't think a lot of the people really knew what was happening. There were lots of people just strolling around a block away, not knowing what was going on."

Vanderhoek said it appeared a police cruiser had rammed a black Dodge mega cab truck. There was one person in the truck, he said, and it appeared the person was deceased.

One witness said a police cruiser rammed into a black Dodge truck in downtown St. Paul on Friday. (@RheaLabrie/Twitter)

A spokesperson for STARS, Alberta's air ambulance service, said due to the circumstances of the situation, most details will have to come from the RCMP.

"What I can confirm is that at 6:43 p.m. STARS responded to St. Paul hospital and transported two patients who had been involved in a motor vehicle collision and sustained gunshot wounds," David Fairbanks wrote in a statement.

St. Paul Mayor Glenn Andersen confirmed that shots were fired but said both RCMP officers and the gunman were in vehicles at the time.

"It's very surprising," said town councillor Ken Kwiatkowski. "This is something you'd probably only see in the movies. For it to happen in St. Paul, it's just unbelievable."

Kwiatkowski said a lot of people in the town of 5,400 would probably know the officers in the detachment, which he described as fairly large.

"I think most people know everyone," he said. "We're a very tight-knit community."

Vanderhoek said he was in "utter disbelief."

"This kind of stuff doesn't happen in St. Paul at all," he said. "It's a shock."

St. Paul is located about 150 kilomtres northeast of Edmonton. (Google Maps)

St. Paul is located about 150 kilometres northeast of Edmonton.