Claressa Shields’ bid to become a three-division champion on Saturday is off after her rival’s coach was allegedly assaulted at the weigh-in.

Unbeaten American Shields, 24, was set to face Croatian boxer Ivana Habazin, 29, for the vacant WBC women’s light-middleweight world title.

But Habazin’s trainer James Ali Bashir was taken to hospital with head injuries following Friday’s weigh-in.

The incident prompted the WBC to cancel the bout.

“The WBC strongly condemns any act of violence in any event related to our sport, and specially the horrible attack which took place in an official activity surrounding this event,” the body said.

“The WBC is certain that the corresponding authorities will apply the full extent to the law to this regrettable incident,” it added.

Bashir was seen arguing with an unidentified person after the two fighters had been on the scales at the pre-fight event in Flint, Michigan – Shields’ home town.

The trainer is well-known in the boxing world, having previously worked with the likes of former world heavyweight champion Wladimir Klitschko.

Two-time Olympic champion Shields is unbeaten since turning professional and was set to fight in her hometown as a professional for the first time.

She has already won titles at middleweight and super-middleweight in just nine fights and had she won on Saturday, would have become the fastest fighter to win titles in three divisions.

It is not yet clear if the fight will be rescheduled but the WBC said it may take action if its rules have been broken: “The WBC will monitor the investigation and resolution of the case, and will then determine if an actionable WBC violation of any WBC Rule, Regulation or Code of Ethics took place,” it said.