Calgary police are looking for a woman believed responsible for six convenience store robberies overnight and reminding store owners and employees to be safety conscious.

The robberies happened between 11:30 p.m. Friday and just after 6 a.m. Saturday in the southwest and northwest quadrants of the city.

A woman went into at least six convenience stores and gas stations carrying a blunt object described as a bar or a stick and threatening staff, demanding money and cigarettes.

The woman's face was covered but she is described as 25 to 40 years old, between five foot five and six feet tall with a slim build and blonde or brown hair.

Police said in an email surveillance photos of the suspects are not being released to assist in the investigation.

Police are also offering safety tips for store owners and employees, including:

Ensure windows are clear and visible to outside witnesses.

Provide ample lighting.

Cash registers should be located so as to allow a clear view for passing motorists, pedestrians and police officers.

Do not keep large amounts of cash on the premise.

Use a drop safe or night deposit. When making night deposits have someone with you, stagger your delivery times and routes, and do not carry money in sight.

Equip your business with good-quality video surveillance. If you have a system in place, ensure it is working and the camera is aligned with the cash register or doorway area.

During a robbery: