The International Olympic Committee (IOC) has been asked by South Korea to bar Japan from using the “Rising Sun” flag at next year’s Tokyo games, Seoul’s sports ministry said on Wednesday.

South Korea’s sports ministry sent a letter to the IOC to express its “disappointment” over Tokyo’s organising committee’s decision to allow the “Rising Sun” ensign or kyokujitsuki to be displayed, claiming it represents a “militaristic and imperial past.”

The ministry said the standard defies the peaceful spirit of the Olympics as it was a symbol of Japan’s imperialist past that reminds Asian countries of “historical wounds and pains,” and it likened it to the swastika used in Nazi Germany.

The flag, which features a red sun with 16 rays radiating from the center, has been used by Japan for many centuries and is still flown by Japan’s Maritime Self-Defense Force. It differs from the country’s official flag, a red disk on a white background, which will be used by its Olympic team.

The International Olympic Committee on Wednesday confirmed it had received the letter, Reuters reports.

“As the IOC has said from the outset of this discussion, sports stadiums should be free of any political demonstration,” an IOC official said.

Relations between the two countries have soured recently over trade issues and threats to end a military intelligence sharing agreement.

Last year Japan withdrew from an international naval review because South Korea asked that Japan not fly the same “Rising Sun” flag on its warships.