As many as 10,000 people took to the streets in San Diego and similar numbers marched in Los Angeles Saturday to protest passage of an anti-gay marriage ballot initiative, authorities said.

Demonstrators began marching through central San Diego at noon, according to police Sgt. Diane Wendell. The event lasted about 90 minutes and was peaceful, with no arrests.

The march in the Silver Lake area of Los Angeles began at Saturday evening and lasted about four hours, said police Sgt. Jake Bushy. No incidents were reported as demonstrators marched down Sunset Boulevard carrying signs and waving banners.

The demonstrations were the largest of several marches that followed Tuesday's passage of Proposition 8, a constitutional amendment banning same-sex marriages and overturning the state Supreme Court decision that legalized such unions in May.

A candlelight vigil in Laguna Beach Saturday evening drew about 1,000 people and police reported no incidents.

On Friday, tensions flared at a vigil at Palm Springs City Hall when a supporter of the gay marriage ban carrying a plastic foam cross clashed with protesters, according to The Desert Sun. The crowd ripped the cross from her hands and stomped on it. Police made no arrests.

About 2,000 people gathered in Long Beach Friday night and there were three arrests. A thousand people also marched Friday in San Francisco.

In Salt Lake City Friday night, a crowd of about 2,000 chanted "Separate church and state" and waved rainbow flags outside the headquarters of the Church of Jesus Christ of Latter-day Saints, which encouraged its members to work to pass the amendment by volunteering their time and money for the campaign.