Singer/songwriter Michelle Shocked has broken her silence after upsetting gay groups with a rant against same-sex marriage at a gig in San Francisco, California on Sunday night (17Mar13).

The Anchorage singer's gig at Yoshi's came to an abrupt end after the born-again Christian rallied against gay unions during her set.

She told fans, "When they stop Prop 8 (the legislation outlawing same-sex marriage in the state) and force priests at gunpoint to marry gays, it will be the downfall of civilisation, and Jesus will come back," and added, "You can go on Twitter and say, 'Michelle Shocked says God hates f**s!'"

Club bosses turned off stage power following her remarks and brought the gig to a close, insisting Shocked would never be welcomed back.

Ten other venue bosses have since cancelled the singer's upcoming dates, and she has been replaced on this summer's (13) Telluride Blues Festival in Colorado following the fall-out from her comments.

Shocked has now responded to the controversy on Twitter.com, writing, "I'm abiding, letting everyone's true colors show before I undertake a personal response to each & every tweet... (I) am neither against a woman's right to choose nor gay marriage. Am a fundamentalist tho."

Meanwhile, gay rights activist John Becker has launched a petition on website Change.org, demanding that Shocked be held responsible for her hate speech. He has also urging more than a dozen venues to cancel her upcoming shows.

A statement from Becker reads: "Freedom of speech and artistic expression are critically important, but this isn't free speech. This is hate speech... Anti-gay hate speech can have serious consequences including legitimizing bullying and hate crimes, and increasing victims' risk of anxiety, depression, and suicide."