By Dan Whitcomb

LOS ANGELES (Reuters) - An 18-year-old black man who was shot to death by Los Angeles police over the weekend was fleeing from a suspected stolen car and had turned toward officers with a gun in his hand before they opened fire on him, the city's police chief said on Monday.

The death of Carnell Snell Jr. on Saturday was one of two fatal police shootings of black men in California in the past week that touched off protests and intensified a debate over racial bias and excessive force in U.S. policing.

Los Angeles Police Chief Charlie Beck told reporters on Monday that officers were pursuing a car they believed was stolen when Snell leapt from the backseat and ran, prompting them to give chase on foot.

"At one point during the foot pursuit ... they observed him remove a handgun from his waistband and hold it in his left hand," Beck said.

"He ran into a driveway ... and while holding the handgun in his left hand he turned in the direction of the pursuing officers, at which time an officer-involved shooting occurred," the chief said. "A total of six rounds were fired, and Carnell Snell was sent to the pavement."

Beck said Snell was struck by two rounds and pronounced dead at the scene. The pursuit was caught on surveillance video from a local business, which showed Snell holding the semi-automatic handgun, Beck said.

The incident prompted protests in Los Angeles, including a march on Saturday night in which demonstrators pelted Mayor Eric Garcetti's home with eggs. Four people were arrested following a rally on Sunday night.

Some 100 miles (160 km) to the south, 17 people were arrested over the weekend during demonstrations over the police shooting last Tuesday of Ugandan refugee Alfred Olango at a taco stand in the San Diego suburb of El Cajon.

Police say Olango ignored commands to take his hand out of his pocket before pulling out an object later determined to be a vaping device and aiming it at them in a "shooting stance."

Two videos released by authorities on Friday of that incident have done little to calm community outrage over Olango's death.

The videos, one taken from a camera mounted at the drive-through window of the taco stand and the other from a bystander's cellphone, showed two officers confronting Olango before opening fire, one with a gun and the other with a Taser.

(Reporting by Dan Whitcomb; Editing by Andrew Hay and Peter Cooney)