Three people were killed in a shooting early Monday outside a Walmart store in Oklahoma, including the assailant, police said - the latest in a string of deadly gun attacks at the popular supermarket chain. Danny Ford, the police chief in the town of Duncan, said the shooting -- an apparent domestic dispute -- took place shortly before 10:00 am (1600 GMT) in a parking lot in front of the store.

"We have three individuals that are deceased. We have two white males and a white female. Two of the victims are inside the vehicle, one is outside the vehicle," said Ford. A handgun was also found at the scene, police said. Witnesses told local news channels that the shooter approached his victims while they were inside the vehicle, opening fire on them.