Fifa said on Friday it was investigating a misconduct complaint involving the Zambian team at the Women's World Cup, vowing tough punishment if proven.
It provided no details, citing confidentiality, but media reports said the incident involved coach Bruce Mwape allegedly rubbing a player's breasts.
"We can confirm that a complaint has been received in relation to the Zambian women's national team and this is currently being investigated," a Fifa spokesperson said.
"Fifa takes any allegation of misconduct extremely seriously and has a clear process in place for anyone in football who wants to report an incident."
Zambia were eliminated at the group stage of the tournament in Australia and New Zealand and are now back home.
Allegations of sexual abuse in the Zambian women's set-up surfaced on social media last year, with the Football Association of Zambia opening an investigation.
It said at the time there had been no official complaint, but "we consider these allegations very serious".
Mwape, appointed in 2018, was repeatedly asked about it at the World Cup.
He denied the accusations, calling them "fake", and dismissed suggestions he should resign.
"What environment affecting the team in particular?" he responded before their match with Spain – which they lost 5-0 – when pushed on the subject.
"What are you talking about? I would like to know because there is no way I can retire without reason.
"Maybe your reason is because what you are reading from the media or from the press, but the truth of the matter should actually come out, not just on rumours."
A team spokesperson did not immediately respond on Friday.
Police in New Zealand, where the team was based, said they had not received any complaints.
"However, we were made aware of an alleged incident and after making initial enquiries, no further action was required to be taken," a police spokesperson said.
STRICTEST CONFIDENCE
Football's governing body Fifa stressed that any allegations of abuse were handled in the strictest confidence.
"Where guilt is established, Fifa takes the strongest possible sanctions, including removing people from the game for life. Our track record demonstrates this," it said.
Zambia suffered heavy defeats to Spain and Japan before winning their first-ever World Cup match, downing Costa Rica 3-1.
There have been a series of sexual assault scandals in women's football in recent times, notably in Gabon, Haiti, the United States and Afghanistan.
Earlier this year, Fifa toughened its disciplinary proceedings for sexual assault or harassment in a revised Code of Ethics.
It removed the 10-year limitation period on prosecuting sexual offences and obliges "member associations and confederations to notify Fifa of any decisions rendered on sexual abuse".
