A man who opened fire on a highway in Tennessee targeted police officers and others because he was troubled by incidents involving black people and law enforcement officers, authorities said.

The Tennessee Bureau of Investigation said initial conversations with the suspect, identified as Lakeem Keon Scott, revealed he was troubled by incidents across the US. The suspect is black and the shooting victims are all white.

Investigators said Scott killed one person and injured three others, including a police officer.

Scott had two guns early on Thursday morning when he shot at a motel in Bristol, Tennessee, and then shot at several passing cars. When he was confronted by police, he fired at the three officers who responded.

The suspect was shot by the officers and is being treated at a hospital. He has not yet been charged.

The announcement came just hours after 12 officers were shot at a Black Lives Matter protest in Dallas by a man who police said declared he was angry about police shootings of black men and wanted to exterminate whites. Five of the officers died.

The shooting spree in Tennessee began at around 2.20am local time on Thursday.

The Tennessee Bureau of Investigation alleges Scott - armed with an assault rifle, a pistol and a large amount of ammunition - fired shots through the window of the Days Inn on Volunteer Parkway.

The front desk clerk, Deborah Watts, was struck and injured. Days Inn owner Kiran Patel said he awoke to the sound of gunfire. His wife called the front desk to see what happened and Ms Watts answered and said she had been shot. She remains in the hospital in a serious but stable condition.

The gunman then turned his fire to cars passing on the highway, investigators say.

Newspaper carrier Jennifer Rooney, a 44-year-old mother-of-two, was on her way to pick up papers for the morning delivery when a bullet struck her. The Bristol Herald-Courier reported that her car crashed through a chain link fence.

David Whitman Davis was also injured by flying glass from the gunfire, the TBI said.

Three officers with the Bristol Tennessee Police Department arrived and confronted Scott, who fired on them.

Officer Matthew Cousins was hit in the leg. He was treated for superficial injuries and released.

Scott was stuck by the officers returning fire. He remains in the hospital in serious but stable condition.

The Tennessee Bureau of Investigation said the investigation is ongoing as they work to understand the shooter's motive.

PA Media