A 25-year-old man was shot in Montreal overnight, apparently after he stumbled onto an assault taking place in an apartment building.

It began around 11:20 p.m. Thursday when several men stormed into an apartment on St. Mathieu St. in the block south of Rene Levesque Blvd. and started attacking the 35-year-old resident.

While the assailants were beating up one man, a 25-year-old man walked in.

Surprised, the attackers pulled out a firearm and shot the newcomer in the lower body, then ran off.

The shooting victim was taken to hospital to be treated for his injuries, while the man who was pummelled was also treated.

Police say both men are co-operating to provide a description of the gang of thugs, however at this point officers have not been able to make an arrest.