Fearing a possible walkout on the Rio Olympics by its Women's World Cup championship side, the US Soccer Federation has filed a lawsuit against its women's players union.

The move, made late Wednesday in US District Court at Chicago, asked the court to confirm the current collective bargaining agreement (CBA) that has been in place since 2013 and is set to expire at the end of this year.

Richard Nichols, executive director of the Women's National Team Players Association, told US Soccer he does not believe there to be an agreement in place, a position that would allow the US women's team to strike starting February 24.

"We are confident the court will confirm the existence and validity of the current CBA," a US Soccer statement said.

"While unfortunate, we believe taking this action provides the parties with the most efficient path to a resolution, in an effort to not jeopardize the team's participation in any competitions this year, including the 2016 Olympic Games."

A ruling would set the timing and groundwork for negotiating a new agreement, the players having more leverage if talks must take place in the shadow of Rio.

"We look forward to continuing our work with the players to address their concerns and continuing to help improve the game in the future," the statement said.

Americans have won four of the five Olympic gold medals since the sport was added to the offerings at the 1996 Atlanta Centennial Games, including the past three in a row.

They defeated China 2-1 in the first women's Olympic final, lost to Norway in the 2000 Sydney final, then beat Brazil in the 2004 and 2008 finals and downed Japan 2-1 in the 2012 London Olympics championship match. The US women also beat Japan 5-2 in last year's Women's World Cup final at Vancouver.

Sourc: AFP