WASHINGTON: Former US secretary of state Hillary Clinton, who may be eyeing a run in the 2016 presidential election, on Monday came off the sidelines and announced her support for gay marriage.

While Clinton pushed gay, lesbian and transgender (LGBT) rights during her four-year tenure as America's top diplomat, considering them human rights, she had not until now advocated for gay marriage.

"LGBT Americans are our colleagues, our teachers, our soldiers, our friends, our loved ones. And they are full and equal citizens, and deserve the rights of citizenship. That includes marriage", she says in a nearly six-minute video.

"That's why I support marriage for lesbian and gay couples. I support it personally and as a matter of policy and law, embedded in a broader effort to advance equality and opportunity for LGBT Americans and all Americans."

The video was released by the Human Rights Campaign, a civil rights organization working for gays rights.

It came just days after Clinton's husband, former US president Bill Clinton, urged the Supreme Court to overturn a bill he signed in 1996 defining marriage as a union between a man and a woman, calling it "discriminatory."

During her failed 2008 White House bid, Hillary Clinton stopped short of endorsing gay marriage, favoring civil unions instead.

In the video she acknowledged that "like so many others my personal views have been shaped over time," saying they had been changed by conversations and personal experiences as well as "by the guiding principles of my faith."

"Marriage after all is a fundamental building block of our society, a great joy and yes, a great responsibility," Clinton says.

"To deny the opportunity to any of our daughters and sons solely on the basis of who they are and who they love is to deny them the chance to live up to their own God-given potential."

Clinton stepped down on February 1, and polls show that if she throws her hat into the ring to be the Democratic Party nominee in the 2016 election, she would have a strong edge over any other candidate.

"She is in both parties right now by far, I think, the most interesting candidate, probably the strongest candidate," Obama's former White House election aide David Plouffe said during a Sunday interview.