Spanish footballer Jenni Hermoso has filed a criminal complaint over suspended chief Luis Rubiales's kiss on her lips at the Women's World Cup final.

A source at Spain's public prosecutors office revealed the move on Wednesday, as the crisis for the Spanish football federation (RFEF) deepens.

The complaint, which was filed on Tuesday, is key for a preliminary investigation, which prosecutors at Spain's top criminal court have opened for the alleged crime of "sexual assault," to move forward.

The prosecutor's office of the National Court will formally present its complaint against Rubiales "as soon as possible," the source said.

RFEF president Rubiales sparked a worldwide backlash after forcibly kissing Hermoso during the medal ceremony following Spain's triumph in Sydney on August 20.

Hermoso, 33, later said the unwanted kiss had left her feeling "vulnerable and like the victim of an assault," with a statement on social media describing it as "an impulsive, macho act, out of place and with no type of consent on my part."

Rubiales insists the kiss was consensual.

The National Court said last week it was opening the preliminary probe in light of the "unequivocal nature" of Hermoso's statements, stating it was necessary "to determine their legal significance."

World football governing body FIFA provisionally suspended Rubiales for 90 days after he refused to resign from his post.

Some 81 players went on strike from the women's side in protest after the 46-year-old's fierce defensive speech following the incident, in which he railed against "false feminism." They said they would not return until the RFEF's leadership was changed.

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The federation sacked controversial Spain women's coach Jorge Vilda on Tuesday in the wake of the scandal.

Spain's top sports court (TAD) also agreed to investigate Rubiales after the government lodged a complaint.

Rubiales also came under fire for grabbing his crotch with both hands as he celebrated Spain's win while standing next to Spain's Queen Letizia and her 16-year-old daughter, Princess Sofia. He later apologized.

However the suspended chief said he would continue to defend himself "to prove the truth" over his kiss with Hermoso.

In a statement last week Rubiales reiterated that the kiss was "a mutual and consensual act" with "overflowing jubilation on both sides."

The RFEF apologised for the "totally unacceptable behaviour" of Rubiales on Tuesday and fired Vilda as part of an overhaul. The apology came more than two weeks after the incident.

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