GRAND FORKS, N.D. (AP) — Two people, including the gunman, died and another person was injured in a shooting early Tuesday at a Wal-Mart Supercenter store in Grand Forks, North Dakota, police said.

The shooter was the only person with a gun, and no police officers fired a weapon, according to Lt. Derik Zimmel.

"We do not believe there is any further risk to the public," Zimmel said. He would not go as far as to say the gunman shot himself and provided no details of what led to the shooter's death.

One other person was taken to a hospital with gunshot wounds that were not believed to be life-threatening, Zimmel said. Altru Hospital did not immediately release any information.

Police did not provide information about the gunman or victims. Grand Forks Air Force Base issued a statement saying an airman was involved in the shooting, but did not elaborate.

Officers responded to reports of gunshots a few minutes after 1 a.m.

Andy Legg, who was in the store at the time of the shooting, told WDAZ-TV that he heard "popping sounds" shortly before authorities herded him and other customers to a safe section of the store. He said when the group later left the building they passed a Wal-Mart employee who was covered in blood.

A SWAT team that responded to the scene searched a car in the parking lot but found no threats.

"There are several different layers to ensuring a scene is safe," Zimmel said.

Police were investigating to determine a motive in the shooting, he said.

The Wal-Mart is one of two in the northeastern North Dakota city of about 55,000 people. The store's website says it is open 24 hours. Calls to the store were referred to the company's headquarters, which did not immediately respond to a request for comment.

Zimmel did not have information on how many workers and customers were in the store at the time.