Calgary police are investigating after gunshots were fired downtown on 11th Avenue and First Street southwest following a confrontation between two groups of people around 4 a.m. MT Sunday.

It started with an argument between four to six people at the Black Betty bar a few blocks away earlier in the night, say police.

The two groups then met again, and a man grabbed a gun from his vehicle and fired shots. The offenders then fled the scene, and the group of people without the weapon called police.

"Words were exchanged, and then followed by gunfire," said Duty Insp. Steve Ellefson. "And just exactly how that occurred will be determined through the investigation."

No one was injured, but police say roughly four shots were fired — some hitting a strip mall and a vehicle nearby.

Police are tracking down surveillance video of the scene and they are canvassing the neighbourhood for any witnesses.

"We use all evidence at our disposal and we leave no rocks unturned," said Ellefson.