SAN FRANCISCO (AP) – Los Angeles Mayor Antonio Villaraigosa pulled out as keynote speaker for a gay rights group’s fund-raising event scheduled for July 26 following intense lobbying from transgender activists angry over the group’s stand on a federal gay rights bill.

Villaraigosa was scheduled to headline the Human Rights Campaign dinner scheduled for Saturday night in San Francisco. San Francisco city officials and many prominent gay rights leaders already had agreed not to attend the event, which has been billed as a fund-raiser to help defeat a November ballot measure that would again ban same-sex marriage in California.

The Human Rights Campaign is one of the nation’s most prominent gay rights organizations and the Washington-based group already has given more than $500,000 to defeat the same-sex marriage measure. But many transgender activists and their allies have been angry at the group since the fall, when its leaders agreed to support a federal job discrimination ban that protected gays, lesbians and bisexuals – but not transgender people.

Matt Szabo, Villaraigosa’s spokesman, said the mayor’s decision was more a byproduct of the Human Rights Campaign controversy than a snub of the group itself.

When Villaraigosa agreed to appear at the dinner at the Westin St. Francis Hotel, he was unaware that the San Francisco Labor Council had urged its members to boycott the event, which would have put the Democratic mayor, who is mentioned as a possible 2010 gubernatorial candidate, in the position of having to cross a union picket line, according to Szabo.

Some activists were planning to hold a counter-gala outside the hotel on Saturday night.

“We made a commitment and we understood the controversy, but we are now aware the Labor Council had voted for an official boycott,” he said. Szabo added that Villaraigosa searched for a way to be able to fulfill the obligation before alerting the Human Rights Campaign late Friday night that he was canceling his appearance.

The Human Rights Campaign was part of a broad coalition of civil rights groups that promoted a job bias measure – the Employment Non-Discrimination Act – introduced by Rep. Barney Frank that originally would have included protections for transgender people. After Frank concluded the bill would fail unless the transgender safeguards were removed, many groups opposed the amended legislation while HRC continued to back it.

The bill passed the House and its supporters are working toward a vote in the Senate.

Brad Luna, a spokesman for the Human Rights Campaign, said in a statement issued Saturday that the protest “has nothing to do with organized labor” and that the Washington-based organization was committed to the civil rights of transgender people as well as gay men and lesbians.

“And as we have an open dialogue about the best way to move forward, let us never forget that we are still a community of brothers and sisters standing as one to advance equality for all GLBT people,” Luna said.