SYDNEY (AP) A peak players' union says Australia's two-match tour against the Women's World Cup champion U.S. team has been called off as negotiations continue over a new collective bargaining agreement.

Beau Busch of Professional Footballers Australia, a union representing both male and female players, said the tour had been called off late Wednesday afternoon, a day after players on the Matildas women's team refused to show up at a practice session in Sydney.

Football Federation Australian chief executive David Gallop had earlier said the series was ''looking very unlikely'' because of the players' actions.

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Gallop on Wednesday said 60,000 seats had been sold for the Australia vs. U.S. women's matches in Detroit on Sept. 17 and Birmingham, Alabama on Sept. 20.

The union is seeking an increase in wages, international match payments and improvements in accommodation and other benefits for the women's team.

The men's national team boycotted community events before a World Cup qualifier in Perth last week.