After a federal judge upheld a decision to legalise marriage rights for same-sex couples in the American state of Utah earlier this week, state lawyers have now announced they are attempting to take their case to the Supreme Court.

On Monday, US District Judge Robert Shelby refused to block his own ruling making equal marriage legal in the state.

Spokesman for the Utah attorney general’s office Ryan Bruckman has called the ruling “disappointing,” but added “we just have to take it to the next level.”

According to Associated Press, Carl Tobias, a constitutional law professor at the University of Richmond, said he expects the US Supreme Court to make a decision by Friday.

Mr Tobias added that he doubts the case will hold much weight, as two courts have already rejected it and marriages have been taking place for days now.

“The longer this goes on, the less likely it becomes that any court is going to entertain a stay,” he said.

Last Friday, same-sex couples in Utah began queuing to marry after Judge Shelby ruled that the state’s equal marriage ban was unconstitutional.

About 900 gay couples have obtained licenses since Friday, with most of the activity in Salt Lake City.

Utah – better known for the Mormon Church than for progressive politics – is the 18th US state to legalise equal marriage.

On Monday, Republican Governor Gary Herbert said the judge’s ruling had resulted in “a lot of chaos”.

“This uncertainty is creating a lot of problems for us with the conflicting laws in the state of Utah, what the clerks should be doing, what the tax laws are going to be,” he said in a statement.