A Walmart logo forms part of a sign outside a Walmart store. File picture: Steven Senne/AP

Duncan, Oklahoma - Two men and a woman were fatally shot Monday outside a Walmart store in southwestern Oklahoma, the chief of police said.

Two victims were shot inside a car and the third was in the parking lot outside the store in Duncan, Police Chief Danny Ford said.

Police are looking for witnesses to the shooting, Ford said.

No staff members were involved in the shooting and the store was not evacuated, Walmart spokeswoman LeMia Jenkins said in an email.

“This was an isolated incident in the parking lot and was not an active shooter situation,” Jenkins said.

Police said in a Facebook post that a handgun was found at the scene.

Duncan is about 80 miles (130 kilometres) south of Oklahoma City.

No staff members were involved in the shooting and the store was not evacuated, Walmart spokeswoman LeMia Jenkins said in an email.

“This was an isolated incident in the parking lot and was not an active shooter situation,” Jenkins said.

* Walmart hired off-duty officers at dozens of its stores across El Paso, where a gunman opened fire in August at one of the retail giant's locations and killed 22 people. The store where the attack happened was reopened on November 14 amid ongoing lawsuits over safety.

AP