The US Congress approved a bill on same-sex marriage and sent it to the White House.
The House of Representatives passed the Respect for Marriage Act in a 258-169-1 vote on Thursday, a week after it went through the Senate, reports Xinhua news agency.
In a statement, President Joe Biden called the approval "a critical step to ensure that Americans have the right to marry the person they love".
"The bipartisan passage of the Respect for Marriage Act will give peace of mind to millions of LGBTQI+ and interracial couples who are now guaranteed the rights and protections to which they and their children are entitled," Biden was quoted as saying in a statement issued by the White House.
The President further said that "we must never stop fighting for full equality for LGBTQI+ Americans and all Americans".
The legislation was introduced this summer after a conservative Supreme Court justice signaled that rulings on marriage equality and contraception should be reconsidered.
While the bill would not set a national requirement that all states must legalise same-sex marriage, it would require individual states to recognise another state's legal marriage.
In the event the Supreme Court might overturn its 2015 Obergefell v. Hodges decision that legalised same-sex marriage, a state could still pass a law to ban same-sex marriage, but that state would be required to recognise a same-sex marriage from another state.