Biden signs bill on same-sex marriage

US President Joe Biden has signed a new landmark bill which establishes statutory authority for same-sex and interracial marriages.

Biden signed the Respect for Marriage Act on Tuesday before thousands of guests on the South Lawn in the White House.

"Marriage is a simple proposition. Who do you love? And will you be loyal to that person you love? It's not more complicated than that," CNN quoted the President as saying.

He said the law recognises that "everyone should have the right to answer those questions for themselves without the government interference," and secures the federal "protections that come with marriage."

"For most of our nation's history, we denied interracial couples and same sex couples from these protections. It failed to treat them with equal dignity and respect.

"And now, this law requires an interracial marriage and same-sex marriage must be recognized as legal in every state in the nation," Biden was quoted as saying.

The House of Representatives had passed the legislation in a 258-169-1 vote on December 8, with 39 Republicans joining the Democrats in support, after getting through the Senate a week before with 12 Republican senators.

The new law officially voids the 1996 Defense of Marriage Act, which defined marriage as between a man and a woman.

It mandates that states honour the validity of out-of-state marriage licenses, including same-sex and interracial unions.

The legislation was introduced this summer after a conservative Supreme Court justice signaled that rulings on marriage equality and contraception should be reconsidered.