Workers were tied up for four hours during an attack by armed men at a legal cannabis grow-op in Ontario, police have confirmed.

According to Durham Region police, five men carrying guns approached a small group of workers tending to a legal outdoor marijuana grow operation early Thursday morning in Beaverton, Ont.

Police say four of the employees were forced into a security trailer and tied up. The suspects then took the staff’s personal belongings and several garbage bags full of dried cannabis from a storage barn.

The suspects also stole one of the worker’s cars to make their escape. The workers were eventually able to free themselves and call police.

Officers from the Durham Regional Police Service searched the area, but no arrests were made.

The stolen vehicle was found parked a “distance away”, police said.

The service has appealed to anyone with information about the incident to contact them.

The first suspect is a white male with a French accent, between 40 and 45 years old, 5’10” tall, about 140 pounds, with short grey hair.

The second man is also white, between 32 and 35 years old, 5’10” tall, about 150 pounds, with short black hair and a full beard. He was wearing a ski mask.

The remaining three suspects were only described as male.

Anyone with information is asked to contact the robbery unit or Crime Stoppers.