WASHINGTON — The Obama administration on Friday made the latest contribution to a fast-moving legal battle over same-sex marriage rights as the Justice Department said that the federal government would recognize as lawful the marriages of some 1,300 same-sex couples in Utah even though the state government is largely refusing to do so.

The announcement furthered President Obama’s self-described evolution on same-sex marriage rights. He was once a politician who said he was “not in favor of gay marriage” and repeatedly invoked the rights of states to decide how marriage should be defined.

More recently, he said “I think same-sex couples should be able to get married,” and now his administration appears to be edging closer to confronting a state government over its refusal to recognize such rights.

The statement also provided a new twist in a fight that has pitted notions of individual equality against the right of states to define marriage as a majority of their voters see fit. It added to legal confusion surrounding the status of couples who married in a brief window after a Federal District Court judge unexpectedly struck down Utah’s ban on same-sex marriages last month, before the Supreme Court stayed the ruling on Monday, effectively shutting down any further same-sex nuptials in the state for the duration of the litigation.