More than 1,000 gay marriages will not be recognized by Utah with the US Supreme Court suspending the gay marriages that took place after a judge allowed them.
A letter by Utah governor Gary Herbert to officials said the western US state -- which had opposed the district court ruling opening the way for gay weddings -- must obey the top US federal court's decision freezing them again.
The Supreme Court on Monday temporarily blocked gay marriages, after Utah filed an emergency request to stay the judge's ruling, which struck down as unconstitutional a state law banning same-sex marriage.
Some 1,300 marriage licenses for same-sex couples were issued in the 17 days between the two rulings in Utah, a conservative state with a large Mormon population, according to the Salt Lake Tribune.
"After the district court decision was issued on Friday, December 20th, some same-sex couples availed themselves of the opportunity to marry and to the status granted by the state to married persons," said the letter.
"With the district court injunction now stayed, the original laws governing marriage in Utah return to effect pending final resolution by the courts."
Gay rights campaigners slammed the governor's announcement, and the Supreme Court.
"Today's decision harms hundreds of Utah families and denies them the respect and basic protections that they deserve as legally married couples," said Human Rights Campaign (HRC) president Chad Griffin.
"Governor Herbert has once again planted himself firmly on the side of discrimination by preserving the second-class status he believes gay and lesbian Utahans merit."
Griffin added: "These families deserve better and I have no doubt the courts will soon grant them the justice and equality that our Constitution demands."
In his December 20 ruling, federal district judge Robert Shelby said the Utah ban -- approved by voters in a referendum in 2004 -- violated the right of same-sex couples to equal protection under the law.
Seventeen US states and the federal capital Washington DC have so far legalized same-sex marriage.