Authorities say a customer and an employee of the Walmart in Mount Vernon, Washington, along with three 19-year-old men, were injured in a shooting inside the store.
The Seattle Times reports police were called for reports of shots being fired inside the building shortly before 10 p.m. Sunday.
Police investigators believe the shooting occurred after a group of men entered the store and got into "an altercation" with another group of men already inside the store, police said.
A 72-year-old customer and a 24-year-old employee were injured, as were three 19-year-old men who had been involved in the altercation, police said.
According to police, three people were taken to Skagit Valley Hospital by medics and two others arrived in private vehicles.
Police said they did not know the current conditions of the people injured.
An investigation continues.
Mount Vernon is about 60 miles (97 kilometers) north of Seattle.