Emergency personnel work the scene of a deadly shooting at a shopping mall in Allen, Texas on May 6, 2023
Emergency personnel work the scene of a deadly shooting at a shopping mall in Allen, Texas on May 6, 2023 AFP

A heavily-armed man stormed a shopping mall in the US state of Texas on Saturday, shooting dead eight people and wounding several others before he was killed by a police officer at the busy complex.

Video footage circulating online showed the shooter getting out of a sedan in the mall's parking lot before opening fire on people walking nearby.

An officer inside on an unrelated call quickly responded to the gunfire and "neutralized" the shooter as scenes of panic broke out at the sprawling facility in Allen, police said.

The identity of the shooter was not released. His body, sprawled on a sidewalk, was one of seven deaths at the mall when more police arrived.

Two others died in the hospital while "three are in critical surgery, and four are stable," said Allen fire chief Jonathan Boyd.

The attack is the latest deadly gun violence to convulse the United States, a country awash in firearms and which has already endured 199 mass shootings this year, according to the Gun Violence Archive, a non-governmental organization which defines a mass shooting as four or more people wounded or killed.

The gunfire at Allen Premium Outlets, 35 miles (55 kilometers) north of Dallas, began around 3:30 pm (2030 GMT), when it was busy with weekend shoppers, police said.

The officer in the mall "heard gunshots, went to the gunshots, engaged the suspect and neutralized the suspect," said chief Brian Harvey of the Allen police department.

Some of the victims were as young as five years old, a hospital official told NBC News.

Texas Governor Greg Abbott called the mass shooting an "unspeakable tragedy."

President Joe Biden "has been briefed on the shooting," a White House official told reporters.

Local officials hailed the actions of the police officer who charged and killed the shooter.

"We owe a debt of gratitude to first responders that ran toward the gunfire and acted swiftly to neutralize the threat," said Keith Self, a Republican congressman whose district includes the city of Allen.

The police chief later said authorities believe the unidentified shooter "acted alone." CNN showed a cropped photograph of the apparent shooter dead on the ground, wearing tactical gear with extra magazines, and with an AR-15-style rifle at his side.

Steven Spainhouer said he rushed to the scene and performed CPR on victims before the official first responders arrived, and he was confronted with haunting, graphic images.

Finding one female victim on the ground, "I felt for her pulse, pulled her head to the side, and she had no face," Spainhouer told CBS News. He found the son of another victim lying under his dead mother and "covered head to toe" in blood.

"It's just unfathomable to see the carnage," he said.

Janet St. James, a spokesperson for Medical City Healthcare, which operates multiple trauma facilities in North Texas, said it received eight patients from the shooting, ranging in age from five to 61, NBC News reported.

"Allen is a proud and safe city which makes today's senseless act of violence even more shocking," mayor Ken Fulk said in a statement.

"I want to commend our police and fire departments for their quick response. Their thorough training not to hesitate to move toward the threat likely saved more lives today."

Jaynal Pervez, who arrived at the mall while his daughter was inside, told CNN: "There's no more safe places. I don't know what to do."

Pervez later told broadcaster CBS that the scenes in the mall parking lot had been chaotic.

"I saw the shoes around there, people's cell phones on the street," he said.

With more firearms than inhabitants, the United States has the highest rate of gun deaths of any developed country -- 49,000 in 2021, up from 45,000 the year before.