(CNN) -- The Los Angeles County Registrar's Office stopped issuing same-sex marriage licenses after the apparent passage of a ballot measure to eliminate the right of gay couples to marry, the agency said Wednesday.
Voters in California, Arizona and Florida weighed in on constitutional bans on same-sex marriage.
As of 11:30 p.m. ET, 52 percent of voters had approved California's Proposition 8, with 99 percent of precincts reporting.
"This is a great day for marriage," Ron Prentice, chairman of ProtectMarriage.com, said in a statement. "The people of California stood up for traditional marriage and reclaimed this great institution."
The amendment to the state constitution overrides a state Supreme Court ruling in May that legalized same-sex marriage. iReport.com: Share your thoughts on same-sex marriage
The decision to suspend the marriage licenses was based on the Secretary of State's semi-official canvass results from Election Night and a California State Constitutional provision that says a proposed amendment "shall be submitted to the electors and if approved by a majority of votes thereon takes effect the day after the election," Registrar-Recorder/County Clerk Dean Logan said in a news release.
The agency said it would act accordingly if it is directed to reverse course or take further action in the future.
Thousands of demonstrators took to the streets of Los Angeles Wednesday to vent their disappointment at the apparent passage of a ballot initiative to ban gay and lesbian marriages.
The demonstrators peacefully rallied in West Hollywood, holding placards and waving gay pride flags. Elsewhere, hundreds of protesters staged a half-hour sit-in outside CNN's Los Angeles bureau on Sunset Boulevard. The demonstrators chanted slogans and banged on the building's glass doors but then dispersed without incident.
Talk show host Ellen DeGeneres said she is "saddened beyond belief" over the proposed amendment. iReport.com: Historic day was 'bittersweet'
DeGeneres, who wed actress Portia de Rossi in August, said in a statement Wednesday to The Associated Press that she, "like millions of Americans, felt like we had taken a giant step toward equality" by electing Barack Obama as president.
The measure was one of three stunning blows to supporters of same-sex unions in Tuesday's election, after voters in Arizona and Florida also approved constitutional amendments recognizing marriage only as a union between one man and one woman.
In Arizona, where a similar measure failed in 2006, Proposition 102 passed with 56 percent of the vote. Florida voters approved that state's amendment, 62 percent to 38 percent.
Arizona, California and Florida were the only states to weigh constitutional amendments banning same-sex unions this year, down from 11 states in the 2004 election.