SALT LAKE CITY — Utah took its fight against same-sex marriage to the United States Supreme Court on Tuesday, asking the court to suspend same-sex unions that became legal when a judge struck down the state's voter-approved ban.

The state wants the marriages to stop while it appeals a decision Dec. 20 by Judge Robert J. Shelby of United States District Court that banning gay couples from marrying violated their right to equal treatment under the Constitution.

In papers filed Tuesday, the state asked Justice Sonia Sotomayor to overturn court decisions to let the marriages go forward. Justice Sotomayor handles emergency requests from Utah and other Rocky Mountain states, and she is expected to refer it to the entire court. The justices could rule within days.

Nearly two-thirds of Utah's 2.8 million residents are Mormons and they dominate the state's legal and political circles. Judge Shelby's decision came as a shock to many in the state, which approved the ban on same-sex marriage in 2004.

Since the judge's decision, more than 900 gay couples in Utah have gotten marriage licenses. Judge Shelby and the United States Court of Appeals for the 10th Circuit have already refused to halt weddings while the state appeals.