Freestyle skier Nobuyuki Nishi revealed Friday that he has apologized for wearing a hat with a design resembling a controversial Japanese wartime flag at the Pyeongchang Olympic athletes' village.

Speaking to reporters after finishing the first round of men's moguls qualifying in 16th place, Nishi said he was unaware of any negative connotations from the hat that was reminiscent of the rising sun flag used by the Imperial Japanese Army in World War II.

"I bought the hat in Switzerland and I didn't realize what was wrong with it," the 32-year-old said. "I'm sorry for causing trouble."

South Korea's Joongang Daily reported in its online edition the previous day that Nishi was pictured wearing the hat in a photo uploaded to the International Olympic Committee's official Instagram account.

In the since-deleted post on the photo-sharing app, the IOC had uploaded candid images of athletes inside the village, including the picture of Nishi chatting with a member of Slovenia's Olympic team.

The rising sun flag, still flown by the Japanese Maritime Self-Defense Force, is seen as a symbol of Japan's wartime aggression in South Korea and many other Asian countries.

The J. League's Kawasaki Frontale were disciplined by the Asian Football Confederation after two fans nearly sparked a riot by raising the flag during an Asian Champions League away match against South Korean side Suwon Bluewings last April.

The Japanese Olympic Committee, via the Ski Association of Japan, instructed Nishi to "avoid clothing that could cause misunderstanding."