An advertisement has been posted in the Washington Post raising issue with the U.S. daily’s description of the waters between South Korea and Japan as the “Sea of Japan.”

South Korean pop singer Kim Jang-hoon and visiting professor at Sungshin Women’s University and public relations expert Suh Gyung-duk posted the ad in the U.S. daily on Wednesday.

The ad says the paper made "a small but significant error" by using the term “Sea of Japan,” claiming that there is no Sea of Japan in the world and that the label only exists in the thinking of the Japanese government in its attempts to distort history. The ad said the body of water has been referred to as the East Sea by many nations over the past two-thousand years. It also promoted South Korea’s territorial sovereignty over the Dokdo islets.

Kim and Suh said they decided to post the ad after discovering that the New York Times, the Wall Street Journal and the Washington Post have not referred to the waters as the “East Sea” in their articles over the past ten years.