US authorities are searching a rugged and hilly area of south-eastern Kentucky for a man suspected of shooting at nine vehicles and wounding five people on a busy highway.

Joseph A Couch, 32, was named as a suspect in Saturday’s shootings on Interstate 75 after authorities recovered his SUV on a service road near the crime scene.

They later found a semi-automatic weapon nearby that they believe was used in the shooting, said Deputy Gilbert Acciardo, a spokesperson for the Laurel County Sheriff’s Office.

The search was focused on the remote area around where the shootings happened, which is north of London, a community of about 8,000 people roughly 75 miles south of Lexington.

“We’re going to go in and we’re going to find this guy,” Mr Acciardo told reporters as law enforcement raced to find Couch before darkness fell in the remote, densely forested area.

Kentucky Shooting
Deputy Gilbert Acciardo, of Laurel County Sheriff’s Office, spoke at a news conference about the shooting along Interstate 75 (Timothy D Easley/AP)

Authorities consider Couch to be armed and dangerous, and they cautioned members of the public who might spot him not to approach him.

Couch is from Woodbine, a small community about 20 miles south of the shooting scene.

Mr Acciardo said law enforcement zeroed in on him Saturday after they found his abandoned vehicle. Investigators found an AR-15 rifle on Sunday in an elevated wooded area next to highway “that he could have shot down upon the interstate from”, Mr Acciardo said.

Couch was initially considered a person of interest in the case until he was upgraded to a suspect on Sunday based on the “totality of everything” law enforcement has found out so far, Mr Acciardo said.

Authorities believe there was only one gunman and Mr Acciardo said they do not think the shooting was sparked by road rage. He said it appeared to be a “random act” of violence.

“There’s been some speculation, but we’re not ready to address that at this point,” he said.

Kentucky Shooting
An image released by London Police Department in Kentucky shows suspect Joseph A Couch (London Police Department/AP)

Mr Acciardo said authorities were notified at about 5.30pm on Saturday about gunshots along the highway near exit 49.

An individual who was “off that exit” fired multiple rounds into the northbound and southbound lanes, striking nine vehicles and wounding five people, he said.

“When our first two units got to the scene there, they said it was a madhouse: people on the sides of the road, emergency flashers going, bullet holes, windows shot out, nine vehicles shot. Can you imagine that? Just chaotic,” Mr Acciardo said during a news conference.

The wounded — one person from Kentucky and the others from out of state — were in a stable condition in hospital early on Sunday. Some had “very serious” injuries, including one who was shot in the face, Mr Acciardo said.

Residents of Laurel County were on edge as authorities searched with a drone, helicopter and on foot in a remote and sparsely populated wooded area near the highway.

Mr Acciardo said authorities had been “bombarded” with a hundred or more calls from people claiming to have seen Couch at places including a grocery store. State lawmakers from Laurel County urged residents in the area to stay at home during the search.