Kentucky highway shooting manhunt heads into second day

Kentucky police are searching a remote, heavily wooded area for a suspected gunman who opened fire on vehicles travelling a rural stretch of Interstate 75 a day earlier, shooting and injuring five people.

Authorities urged residents to stay away from the site of the manhunt, as search teams scoured a rugged, rocky area near the interstate some 12km from the city of London in southeastern Kentucky where they believe the gunman was contained.

Officials named Joseph Couch, 32, as a suspect after discovering a car registered to him parked on a service road near the shooting site. A rifle case was recovered from the vehicle, and an AR rifle was found near the car on Sunday afternoon, the Laurel County Sheriff's office said.

Laurel County public schools cancelled Monday classes out of an abundance of caution on Sunday evening, and the major of London, Kentucky, Randall Weddle, urged residents to steer clear of the shooting scene.

"Stay home. Let the first responders do their jobs," Weddle told a news conference on Sunday evening.

Difficult terrain has complicated the manhunt, which includes a helicopter and a drone with infrared technology and involves federal, state and local agencies.

"That's probably one of the most remote exits on I-75," Deputy Gilbert Acciardo of the Laurel County Sheriff's Office told reporters. "It's a big task. We want to get him before it gets dark again."

Investigators have not determined a motive for the shooting, Acciardo said.

The incident began on Sunday AEST, when officers responded to reports of gunshots at vehicles on the highway.

The shots came from a hillside overlooking the highway, Acciardo said, describing a chaotic scene with bullet-riddled cars pulled onto the shoulder.

Five people were in stable condition despite some serious injuries, including one victim who was shot in the face and another in the arm.

Nine vehicles in all were struck by bullets, according to the sheriff's office. The attack shut down the highway for several hours. The shooting took place three days after two students and two teachers were killed, and nine others wounded, at a high school in Winder, Georgia.

A 14-year-old student and his father, suspected of giving his son access to the gun used in the shooting, have been charged.