Dallas/IBNS: At least nine people were killed as a shooter went on a rampage at an outlet mall in US' Texas on Saturday, media reports said.

Seven others have been injured in the shooting incident.

"(We) found seven deceased individuals on scene. We transported nine individuals to the hospital... Of those we transported, two have since died," said fire chief Jonathan Boyd of Allen, the Dallas suburb where the shooting took place.

A police officer reached the mall after getting an unrelated call when gunfire broke out around 3:30 pm (2030 GMT), said chief Brian Harvey of the Allen, Texas, police department.

"He heard gunshots, went to the gunshots, engaged the suspect and neutralized the suspect," Harvey was quoted as saying in the media. "He also then called for ambulances."

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

Authorities initially thought there might be a second shooter at Allen Premium Outlets, a sprawling shopping complex in the city of Allen, 25 miles (40 kilometers) north of Dallas, CNN said.

Police then searched through stores in the mall, and photos and drone video from the scene showed shoppers and store employees rushing into parking lots.

The police later said the shooter was wearing tactical gear and "acted alone."