The United States women's soccer team's offer of equal pay was dismissed by a court, with the judge rejecting players' claims that they were underpaid compared to men.
The lawsuit was filed by 28 players from the women's national team last year against the US Football Federation (USSF).
They were seeking $ 66 million (£ 52.8 million) in damages under the Equal Pay Act.
Molly Levinson, a spokesman for the players, said he planned to appeal the decision.
"We are shocked and disappointed," said Levinson. "We are not going to give up our hard work for equal pay.
"We are confident in our case and firm in our commitment to ensure that girls and women who practice this sport are not less valued just because of their sex."
Joe Biden, the Democratic candidate for the US presidency in this year's election, told the team not to "give up on this fight", adding, "This isn't over yet.
"For American football: equal pay now. Or, when I'm president, you can go elsewhere to get funding for the World Cup."
Federal judge Gary Klausner has allowed the case of players for unfair treatment in travel, housing and medical care to go to trial, which is scheduled for June 16 in Los Angeles.
In making its decision, the court said: "The women's team received more in accumulated and average terms per game than the men's team during the class period."
The US team won the Women's World Cup last summer for their fourth overall title. They also won five Olympic gold medals.
After the claim for equal pay was dismissed, striker Megan Rapinoe, who won the Golden Ball and Golden Boot at last year's World Cup, tweeted: "We will never stop fighting for equality".
American striker colleague Alex Morgan said: "Although it is disappointing to hear this news, it will not discourage us in our fight for equality."
The USSF said it wanted to work with the team to "chart a positive path for the game's growth here at home and around the world".
His statement added: "American football is the world leader in women's play on and off the field and we are committed to continuing that work."
Former USSF President Carlos Cordeiro resigned in March, after lawyers for the US government's football agency placed orders as part of the lawsuit claiming that the employment of a football player in the national team "requires a higher level of skill based on speed and strength "than women.
Before playing Japan in the SheBelieves Cup on March 12, US players turned the top inside out during the warm-up to hide their badges, leaving only the four stars that represent their World Cup successes.
The US men's team reached the quarterfinals of the World Cup in 2002, while their best result was third place in the inaugural tournament in 1930.
The women's case was publicly supported by male players, and in February, the US men's team issued a statement criticize the governing body, saying that "the federation continues to discriminate against women in their wages and working conditions".