BOSTON - Gay rights supporters waving rainbow colours as they marched, chanted and danced in U.S. cities coast to coast Saturday to protest the California vote that banned gay marriage there.

Many cast it as a civil rights issue and urged supporters not to quit the fight for the right of gays and lesbians to wed.

Crowds gathered near public buildings in small communities and major cities including New York, San Francisco and Chicago to vent their frustration, celebrate gay relationships and renew calls for change.

"Civil marriages are a civil right, and we're going to keep fighting until we get the rights we deserve as American citizens," Karen Amico said in Philadelphia.

"We are the American family, we live next door to you, we teach your children, we take care of your elderly," said Heather Baker a special education teacher from Boston who addressed the crowd at Boston's City Hall Plaza. "We need equal rights across the country."

Massachusetts and Connecticut, which began same sex weddings this past week, are the only two U.S. states that allow gay marriage. All 30 states that have voted on gay marriage have enacted bans.

Protests following the vote on Proposition 8 in California, which defined marriage as between a man and a woman, have sometimes been angry and even violent, and demonstrators have targeted faiths that supported the ban, including the Mormon church.

However, representatives of Join the Impact, which organized Saturday's demonstrations, asked supporters to be respectful and refrain from attacking other groups during the rallies.

Seattle blogger Amy Balliett, who started the planning for the protests when she set up a Web page three days after the California vote, said persuasion is impossible without civility.

"If we can move anybody past anger and have a respectful conversation, then you can plant the seed of change," she said.

Balliett said supporters in 300 cities in the United States and other countries were holding marches, and she estimated one million people would participate, based on responses at the websites her group set up.

"We need to show the world when one thing happens to one of us, it happens to all of us," she said.

The protests were widely reported to be peaceful and the mood in Boston was generally upbeat, with attendees dancing to the song "Respect."

Signs cast the fight for gay marriage as the new civil rights movement, including one that read "Gay is the new black."

But anger over the ban and its backers was evident at the protests.

One sign in Chicago read: "Catholic Fascists Stay Out of Politics."

"I just found out that my state doesn't really think I'm a person," said Rose Aplustill, 21, a Boston University student from Los Osos, Calif., who was one of thousands at the Boston rally.

In San Francisco demonstrators took shots at some religious groups that supported the ban, including a sign aimed at the Mormon church and its abandoned practice of polygamy that read: "You have three wives; I want one husband."

Chris Norberg, who married his partner in June, also referred to the racial divisions that arose after exit polls found that majorities of blacks and Hispanics supported the constitutional ban on same-sex marriage.

"They voted against us," Norberg said.

Demonstrators in Washington marched from the U.S. Capitol through the city carrying signs and chanting "One, two, three, four, love is what we're fighting for!"

A public plaza at the foot of New York's Brooklyn Bridge was packed by a cheering crowd, including people who waved rainbow flags and wore pink buttons that said "I do."

Protests were low-key in North Dakota, where people lined a bridge in Fargo carrying signs and flags.

In Chicago, Keith Smith, 42, a postal worker, and his partner, Terry Romo, 34, a Wal-Mart store manager, had photos of their wedding ceremony which they held even though gay marriage is not legal in Illinois.

"We're not going to wait for no law," Smith said. "But time's going to be on our side and it's going to change."