An unidentified gunman shot and killed his wife and four other people in a series of shootings in California before taking his own life, police said.

There was no immediate word on what sparked the shootings that took place at a home and a business in Bakersfield, some 145km north of Los Angeles.

According to police, the man went with his wife to a trucking company in the city of about 375,000.

He then shot and killed a man and then turned his gun on his spouse, and shot her, Kern County Sheriff Donny Youngblood told a news conference.

The man chased and shot another man who showed up, Youngblood said.

The gunman then went to a home where he shot and killed a man and a woman, the sheriff said.

This is the new normal, if you look across the country. Six people lost their lives in a very short period of time

DONNY YOUNGBLOOD, KERN COUNTY SHERIFF

He then carjacked a woman who was driving with her child. The woman and the child escaped and the man drove to a highway where a sheriff’s deputy saw him, Youngblood said. The man pulled into a car park and shot himself when the deputy confronted him.

Youngblood added that the entire incident took place in 10 to 15 minutes, describing the incident as a mass shooting.

“This is the new normal, if you look across the country. Six people lost their lives in a very short period of time,” Youngblood said.

Motive unknown

The sheriff added that authorities were working to determine the motive of the shootings, as well as the connections between the victims and gunman.

“Obviously, these are not random shootings,” Youngblood said.

Authorities have not disclosed the identities of the shooter or victims.

Police recovered a pistol at the scene. Authorities were interviewing about 30 witnesses.

‘Human rights crisis’

The shooting occured just hours after Amnesty International released a report, blaming the US government for allowing gun violence to become a “human rights crisis”.

According to the rights organisation, more than 30,000 people – the majority suicides or homicides – die each year in firearm related incidents.

An average of 106 individuals died a day in 2016 due to gun violence, Amnesty said in its report, released on Wednesday.

Amnesty blamed the US government for not enacting regulations to protect American lives.

“Despite the huge number of guns in circulation and the sheer numbers of people killed by guns each year, there is a shocking lack of federal regulations that could save thousands,” Margaret Huang, executive director of Amnesty International USA, said in a statement.

Calls for stricter gun control were again amplified this year after mass shootings in Maryland, Texas and Florida, among other places.

Last year, the US witnessed the deadliest mass shooting in the country’s modern history after 58 people were killed at a music concert in Las Vegas, Nevada.