Eight children were killed in a shooting spree early Sunday in the southern US state of Louisiana, in what police said appears to have been an incident of domestic violence. 

The incident, which took place just after 6:00 am (1100 GMT) in the city of Shreveport, was the deadliest mass shooting in the United States in more than two years, according to data from the Gun Violence Archive.

The gunman, who was not immediately identified but was reportedly an adult male, was fatally shot by police after a car chase, officials said.

Police Corporal Chris Bordelon told a press conference that the "rather extensive crime scene" spanned three residences, which were being combed for evidence by investigators.

The victims ranged in age from one to 14, Bordelon said. Two other people were struck by gunfire, but their conditions were not immediately known.

"Some of the children inside were his descendants," he added.

The suspect carjacked a vehicle and led police on a chase before officers opened fire and the assailant was killed. No officers were injured, according to state police.

"We do believe him to be the only individual that fired gunshots at these locations," Bordelon said, calling the incident a "domestic disturbance."

Police said more details about the victims and the gunman would be released pending notification of next of kin.

ABC affiliate KTBS reported that the two people wounded were adult women who were shot in the head. The network also said a male child was injured when he jumped from a roof of one of the homes.

One of Louisiana's two US senators, Republican Bill Cassidy, called the incident an episode of "horrific violence" and wished the survivors a speedy recovery.

Louisiana Governor Jeff Landry said he was "heartbroken."

The United States, where firearms are readily available, is a frequent scene of gun violence, with thousands of people killed every year.

"It's a terrible morning in Shreveport and we all mourn with the victims," Mayor Tom Arceneaux said at the press conference.