LAUSANNE, Switzerland: IOC President Thomas Bach has told Ukraine its calls to boycott the 2024 Paris Games over the possible participation of Russian competitors goes against Olympic “principles” as his organization was accused of being “on the wrong side of history.”

In a letter to the Ukrainian National Olympic Committee revealed on Thursday, Bach said Ukraine’s efforts in “pressuring” other countries to boycott the 2024 Games was “extremely regrettable.”

The International Olympic Committee said last month it was exploring a “pathway” to allow Russian and Belarusian competitors to take part in the Paris Olympics, under a neutral flag.

Ukraine has reacted furiously, threatening to pull out of the Games. Nordic and some eastern European countries have said they would join a boycott.

“Threatening a boycott of the Olympic Games which, as you inform me, the NOC of Ukraine is currently considering, goes against the fundamentals of the Olympic Movement and the principles we stand for,” Bach said in the letter to Ukraine’s Olympic chief Vadym Goutzeit.

Bach said the participation of Russian and Belarusian athletes “has not even been discussed in concrete terms yet.”

“Therefore, your letter at this premature stage to your fellow NOCs, to the International Federations, IOC Members and to future Olympic hosts, pressuring them in an attempt to publicly influence their decision-making, has been perceived by the vast majority of them as, at the very least, extremely regrettable,” Bach added.

Bach also blasted what he described as “defamatory statements” made by some Ukraine officials who accused the IOC of being a “promoter of war, murder and destruction.”

Russia and its ally Belarus, which allowed its territory to be used as a launchpad when Moscow began its invasion of Ukraine last February, have been sidelined from most Olympic sports since the war began.

The publication of Bach’s letter comes on the eve of a summit of sports ministers in London on Friday.

At the conference, Ukraine President Volodymyr Zelensky is expected to denounce the potential participation of Russian athletes in the Paris Olympics.

Zelensky has called the plans to allow Russians to take part an attempt “to tell the whole world that terror is somehow acceptable.”

The IOC’s proposed roadmap for athletes’ return to action under a neutral flag, provided they had “not actively supported the war in Ukraine,” has caused deep divisions and heated debate.

Polish Sports Minister Kamil Bortniczuk said he expected around 40 countries to oppose the participation of Russians and Belarusians in the Paris Olympics at Friday’s conference.

The US, however, backs allowing athletes from Russia and Belarus to compete as neutrals while opposing the display of their national flags or emblems.

The controversy has not helped form a unified policy.

For example, Russian and Belarusian tennis players can compete at tour events and Grand Slams albeit not under their national flags.

However, Wimbledon last year imposed a blanket ban on players from the two nations taking part in arguably the sport’s most prestigious Grand Slam event.

Pressure group Global Athlete said Bach’s response to Ukraine concerns shows “the IOC continues to be on the wrong side of history.”

“Their letter is further evidence of the power Russia has over the organization and the Olympic movement,” the group said in a statement released Thursday.

“Sponsors, host cities, and national governments must stop tolerating the IOC’s kowtowing to Russia.”

On Wednesday, the French government and the 2024 Olympic organizers sidestepped the row, a day after Paris Mayor Anne Hidalgo called for a ban over the war in Ukraine.

Hidalgo echoed Zelensky who urged his French counterpart Emmanuel Macron to ban Russians from the Games.

French government spokesman Olivier Veran and Paris Organizing Committee President Tony Estanguet said the decision was the responsibility of the IOC.

Veran told a press briefing that “a decision must be taken by the summer” by the IOC.

“No position has been formally agreed with the IOC yet,” he said. “I will wait for international cooperation to take its course.”

However, he did not rule out an exclusion, speaking of “the steadfast wish of France that every possible sanction be applied fully and entirely.”