Los Angeles, California - A bus hijacking that led to a slow-motion police chase through Los Angeles early Wednesday left one person dead and the alleged gunman in custody, police said.

Officers were called to reports of shots being fired on the city bus just before 1:00 AM as an armed man apparently ordered the driver to deviate from his route, sending some passengers rushing to escape.

Footage shows several police cars following the bus, which is displaying the word "Emergency", as it rolls through darkened city streets.

One person can be seen riding alongside the bus on a bike, filming events, while another does the same from a skateboard.

The chase continued for over an hour, including after officers rolled out spikes to puncture the bus's tires, leaving a trail of smoke from the wheels.

Video then shows a SWAT team surrounding the vehicle with an officer using a megaphone to order everyone out of the bus.

"Metro Bus 5858 this is LAPD. You're surrounded," the officer says. "Come out with your hands up, one by one."

The driver can be seen sitting still with his hands raised.

The SWAT team appears to set off flashbangs as officers with shields storm the bus.

A passenger who police said had been shot as the incident began was taken to hospital but declared dead.

Police praised the driver for his calm reaction to the hijacking, during which he had pressed a panic button to alert officers.

"This operator continued to operate the bus in as safe a manner as he could under the circumstances, with the police trailing him for an hour before the spike strips finally took effect," said Donald Graham of the LAPD.

Los Angeles County Supervisor Janice Hahn described the events as "a nightmare."

"I am grateful to our Metro bus driver who showed incredible composure," she said.

Hahn said there would be a full investigation, adding, "We need ways to prevent people from bringing weapons onto our Metro buses and trains."

Despite being the second biggest city in the US, Los Angeles has a sparse public transport network, with only a few underground train lines serving its millions of people.

The bus network is often used by poorer and more marginalized residents, including the homeless and those with mental health problems.

The hijacking is the latest incident to afflict the public transport network, which in recent months has seen stabbings and shootings.

Los Angeles Mayor Karen Bass has pledged to bolster the network in time for the 2028 Olympics in a bid to hold a "car-free Games."