(Recasts with mayor urging calm)

SAN FRANCISCO, Jan 8 (Reuters) - Oakland authorities pleaded for calm and some businesses closed early in the Californian city on Thursday, one day after rioting over the killing of an unarmed man by transit police.

Mayor Ron Dellums appeared with community leaders to ask the public to remain calm while an investigation continues into the shooting of a black man by a white transit police officer.

"We urged people to remain peaceful," said Dellums' chief of staff, David Chai. "We're hoping for the best."

Cleaning products firm Clorox Corp and health care company Kaiser Permanente said they sent their employees home by early afternoon to ensure their safely, though calm had returned to the city of 400,000 inhabitants.

On Wednesday night, angry demonstrator smashed store windows and burned cars to protest the killing of 22-year-old Oscar Grant on New Year's Day at a Bay Area Rapid Transit (BART) subway station by Johannes Mehserle, a BART police officer.

Oakland police arrested 105 people on charges of vandalism, rioting, unlawful assembly and assault on police officers, police spokesman Jeff Thomason said. All but 21 had been released by Thursday.

Grant was detained by BART police after a scuffle between two groups of young men. Videos recorded by bystanders now circulating on the Internet show Mehserle shooting Grant, who appeared to be face down on the railway platform.

Mehserle resigned on Wednesday.