Vice President Joe Biden on Sunday appeared to go further than he has in the past in expressing support for same-sex marriage.

In an interview on NBC's "Meet the Press," Biden described himself as "absolutely comfortable" with gay couples having the same rights as heterosexual couples.

"Look. I am vice president of the United States of America," Biden said. "The president sets the policy. I am absolutely comfortable with the fact that men marrying men, women marrying women, and heterosexual men and women marrying are entitled to the same exact rights, all the civil rights, all the civil liberties. And quite frankly, I don't see much of a distinction beyond that."

Asked whether the Obama administration in a second term would come out in favor of same-sex marriage, Biden declined to say.

"I can't speak to that. I don't know the answer to that," he said.

Gay rights groups welcomed Biden's comments and said President Barack Obama should follow suit.

"We are encouraged by Vice President Biden's comments, who rightly articulated that loving and committed gay and lesbian couples should be treated equally," Joe Solmonese, president of the Human Rights Campaign, said in a statement. "Now is the time for President Obama to speak out for full marriage equality for same-sex couples."

It was not immediately clear whether Biden was speaking off the cuff or whether his remarks might have been part of a move by the Obama administration to inch closer toward an embrace of same-sex marriage through a high-level surrogate.

The "Meet the Press" interview was taped Friday. Immediately after its airing Sunday morning, a Biden spokesman said that the vice president "was saying what the president has said previously - that committed and loving same-sex couples deserve the same rights and protections enjoyed by all Americans, and that we oppose any effort to roll back those rights."

"That's why we stopped defending the constitutionality of Section 3 of the Defense of Marriage Act in legal challenges and support legislation to repeal it," the aide said. "Beyond that, the vice president was expressing that he, too, is evolving on the issue, after meeting so many committed couples and families in this country."

Obama senior adviser David Axelrod said via Twitter shortly after Biden spoke: "What VP said - that all married couples should have exactly the same legal rights - is precisely POTUS's position."

The White House in February instructed the Justice Department to no longer defend the constitutionality of the Defense of Marriage Act, the 1996 law that bans federal recognition of same-sex marriage. The move has led to a political battle with the Republican-led House, which has moved to defend the law in court.

Biden has previously said that he believes same-sex marriage is "an inevitability," although he has stopped short of endorsing it. Biden said in a December 2010 interview on ABC's "Good Morning America" that he agrees with Obama that he is continually "evolving" on the issue.

Obama has come under criticism from gay rights groups and others for not endorsing same-sex marriage.

The issue is a politically thorny one for Obama. If he were to come out in favor of same-sex marriage, he would risk losing the support of some independents and could be viewed as acting out of political opportunism. If he continues "evolving" on the issue, he risks leaving a key part of his base disenchanted ahead of the November election.

It's an issue that could come to a head when Democrats craft their party platform at the Democratic National Convention.

In speaking about his views on same-sex marriage Sunday, Biden said that "when things really begin to change is when the social culture changes.

"I think 'Will and Grace' probably did more to educate the American public than almost anything anybody's ever done so far," he told host David Gregory, referring to an NBC television series that featured a gay lawyer and his best friend, a heterosexual woman. "And I think people fear that which is different. Now they're beginning to understand."

He declined to say whether he plans to run for president in 2016.