The International Olympic Committee (IOC) says there is no link between a qualifying event for Tokyo 2020 in London and two Turkish fighters catching coronavirus.
London's Copper Box Arena hosted the qualifying tournament two weeks ago, featuring boxers from 40 nations.
It continued for three days, despite virtually every other sport being suspended because of the pandemic.
According to the Turkish Boxing Federation website, athlete Serhat Gler and trainer Seyfullah Dumlupinar contracted the virus after the tournament.
Federation president Eyup Gozgec said: "While the world was taking extreme measures to deal with the virus, I am baffled that an IOC taskforce and the British government allowed the tournament to start, even though many of us had concerns and almost every other sport had shut down."
In a letter to other boxing federations, seen by the Guardian, Gozgec, who is also vice-president of the European Boxing Confederation, said: "Unfortunately, two of our athletes and our Turkish head coach have tested positive for the new type Covid-19 coronavirus after returning to Turkey from London.
"All of them are in treatment now and thankfully they are in good condition. This is the disastrous result of the irresponsibility of the IOC taskforce.
"This virus has been around since December 2019. Therefore, it is inevitable to ask why the European qualification event was not postponed before it took place?
"They did not consider anyone's health, which led them to organise this horrible event."
However, an IOC spokesperson said on Thursday: "Yesterday, the IOC Boxing Task Force (BTF) received news reports regarding participants of the Boxing Road to Tokyo European qualifier held in London from 14-16 March 2020, who reportedly tested positive for COVID-19 following a return to their country.
"Most importantly, the BTF wants to express its sympathy for the affected athletes and officials and wishes them a very speedy and full recovery, and the BTF is in close contact with their respective National Olympic Committees.
"Some news reports appeared to draw a connection between the affected participants and the Boxing Road to Tokyo European qualifier held in London.
"The London event was suspended ten days ago, on 16 March 2020, and the BTF is not aware of any link between the competition and the infection.
"Many participants were in independently organised training camps in Italy, Great Britain and in their home countries before the competition started on 14 March 2020 and have returned home a while ago, so it is not possible to know the source of infection.
"The BTF notes that at the time of the European qualifier in London there were many sports and other events going on in Great Britain, because there were no governmental restrictions or advice on public events in place.
"Nevertheless, in cooperation between the BTF and the Local Organising Committee, precautionary measures before, during and in the follow-up phase of the event were implemented and the event was suspended when the COVID-19 situation developed further.
"Safeguarding the well-being of the athletes, officials and all other participants has always been a top priority for the BTF."