The International Olympic Committee confirmed Thursday that it had sent a letter to National Olympic Committees expressing “concern” with recent claims made by boxing’s troubled governing body AIBA.

The letter from IOC director-general Christophe De Kepper, first revealed by the Inside the Games website, was reportedly a response to a separate letter sent by AIBA’s president Gafur Rakhimov, a controversial Uzbek businessman.

The IOC press office confirmed to AFP that the letter had been sent.

According to Inside the Games, Rakhimov had written to all 206 NOCs indicating that AIBA had “left the troubled past behind us”.

Last month, the IOC froze preparations for boxing at the 2020 Tokyo Games and launched a probe into AIBA, warning it could be stripped of the right to run the competition.

That probe was triggered by the IOC’s concerns about the AIBA’s governance, ethics and financial management as well as the leadership of Rakhimov, whom the US Treasury Department has linked to organised crimes.

Rakhimov denies those claims.

The IOC letter said that Rakhimov did “not at all provide an accurate portrayal of the decisions of the IOC Executive Board in regard to AIBA,” according to an image of text posted online by Inside the Games.

De Kepper underscored that the IOC executive board had expressed a “level of significant concern with AIBA,” which has not yet been resolved.

Relations between the IOC and AIBA were hit hard at the 2016 Rio Olympics when 36 officials and referees were suspended amid allegations of bout fixing.

AIBA’s election of Rakhimov created further friction.