Four soccer players for the Portland Thorns are among the 28 women who filed a lawsuit against the U.S. Soccer Federation on Friday, demanding an end to gender discrimination in the sport.

Tobin Heath and Lindsey Horan, both midfielders, Adrianna Franch, a goalkeeper, and defender Emily Sonnett are the Thorns players listed as plaintiffs in the suit, the Portland Business Journal first reported.

The lawsuit, which was examined by the New York Times, describes "institutionalized gender discrimination," including unequal pay, promotion, support and development.

"Despite the fact that these female and male players are called upon to perform the same job responsibilities on their teams and participate in international competitions for their single common employer, the USSF," the suit reads, "the female players have been consistently paid less money than their male counterparts. This is true even though their performance has been superior to that of the male players – with the female players, in contrast to male players, becoming world champions."

The filing comes three months before the U.S. team is scheduled to play in the Women's World Cup.

The four Thorns listed in the suit and a spokesperson for the team could not immediately be reached for comment.