At least three people are dead after a Monday morning shooting at an Oklahoma Walmart, authorities confirmed.

Officials received a call just before 10 a.m. about gunfire at the site in Duncan, a town of about 22,000 an hour southwest of Oklahoma City.

“At this time we can confirm a shooting in the Walmart parking lot. We have 3 deceased individuals,” the Duncan Police Department said. The news was also confirmed by the Oklahoma Highway Patrol.

Authorities confirmed one man and one woman were found dead inside a car in the retailer’s parking lot, and another male was found dead outside the vehicle. The suspect is dead from an apparent self-inflicted gunshot wound and is among the three deceased individuals, Duncan Police Chief Danny Ford said in a Monday press conference.

Ford added that “several rounds were fired at the car and a handgun was found on scene.” Aerial footage shows several law enforcement officials and a forming crowd at the megastore’s parking lot.

“As this is an active police investigation, we are currently referring additional questions to Law Enforcement and assisting however possible,” Walmart said in a statement to Fox23. The megastore remains open despite the deadly Monday morning incident, one employee in the deli department confirmed to The Daily Beast.

Family members told Fox 25 the shooting was the result of a domestic dispute between a husband and wife. Witnesses told several local television stations the suspect shot the two people inside the car before an armed shopper approached with a gun—prompting him to shoot himself.

While authorities did not go into specifics about the incident, Ford told reporters Monday that “at some point the shooter did walk up to the car,” and added that while an armed civilian was at the scene, he cannot confirm if he intervened before the shooter killed himself.

Ford added the two victims had been inside the store before the shooting and that the female victim was a Walmart employee.

Duncan Public Schools officials confirmed that while all schools are on lockdown, the police department has given them the all clear and classes have resumed.

“Duncan Public Schools is aware of the report of a shooting at Duncan Walmart. As always we are taking every precaution to protect our staff and students. At this time all schools are in lockdown due to this report. Schools will operate as normal, but visitors will not be admitted until police report it is safe,” officials said in a Facebook post.

Lynn Gregston, owner of the adjacent Country Club Care nursing home, told USA Today authorities said the gunman shot himself after firing on two others.

“Everything is in control,” Gregston said, whose storefront is across the street from the Walmart. “We locked it down using our alert system.”

Walmart has become a focal point in the national debate over gun violence. Last week, its superstore near the Mexican border in El Paso reopened, three months after a gunman reportedly targeted Hispanic shoppers at the site and killed 22 people in early August. The retailer hired off-duty police to staff the low-key reopening.

In recent months, and in light of the violence, Walmart said it was reducing its gun and ammunition sales and was requesting that shoppers not carry their weapons into its stores.

On Nov. 1, Oklahoma's new permitless carry law went into effect, allowing most residents over age 21 to carry a firearm in public without a license.