A federal judge dismissed the United States women's soccer team's bid for equal pay on Friday, rejecting claims the players had been underpaid in a crushing defeat for the reigning world champions.

In a 32-page ruling, Judge Gary Klausner of the US District Court for Central California in Los Angeles tossed the women's claim of pay discrimination, ruling in favour of the United States Soccer Federation. Klausner did allow the women's case for unfair treatment in areas such as travel, housing and medical support to proceed to trial, set for June 16 in Los Angeles.

But the judge said the equal pay claims -- the central plank of the case -- had been dismissed because there was evidence the women had turned down an offer to be paid along the lines of the US men's team.

"The history of negotiations between the parties demonstrates that the WNT rejected an offer to be paid under the same pay-to-play structure as the MNT, and the WNT was willing to forgo higher bonuses for benefits, such as greater base compensation and the guarantee of a higher number of contracted players," Klausner wrote.

"Accordingly, plaintiffs cannot now retroactively deem their CBA (collective bargaining agreement) worse than the MNT CBA by reference to what they would have made had they been paid under the MNT's pay-to-play terms structure when they themselves rejected such a structure," he said.

'Shock, disappointment'

The US women were left stunned by their defeat on the pay issue. The women had been seeking back pay of $66 million under the Equal Pay Act.

Prominent US women's team star Megan Rapinoe said after learning of the court's decision that the battle is not over. "We will never stop fighting for EQUALITY," she wrote on Twitter.

A spokeswoman for the players reacted with dismay following Friday's ruling. "We are shocked and disappointed with today's decision, but we will not give up our hard work for equal pay," spokeswoman Molly Levinson said.

"We are confident in our case and steadfast in our commitment to ensuring that girls and women who play this sport will not be valued as lesser just because of their gender. We have learned that there are tremendous obstacles to change; we know that it takes bravery and courage and perseverance to stand up to them."

The increasingly acrimonious lawsuit had taken a dramatic turn in March, when a filing by lawyers for the federation argued that US men's team players required a "higher level of skill-based on speed and strength" than the women. The filing triggered outrage amongst the women's players while influential sponsors such as Coca-Cola voiced disgust at the remarks.

USSF President Carlos Cordeiro later resigned following the uproar, with Rapinoe accusing the USSF of "blatant sexism" in its legal filings. The US women, who clinched back-to-back World Cup wins with victory at last year's finals in France, had based their claim for back pay in the disparities between prize money distributed by FIFA at the men's and women's World Cups.

Germany's men won $35 million for their victory in the 2014 World Cup while France earned $38 million after triumphing in Russia in 2018. The United States women, victors in the 2015 and 2019 World Cups, earned total prize money of $6 million over the two tournaments.