Japan has lodged a protest with South Korea over an online video promoting the use of the name "East Sea" to describe the Sea of Japan, the Japanese government's top spokesman said Wednesday.

The video, uploaded in English and Korean to the South Korean Foreign Ministry's YouTube account, claims, "Japan knows the truth" about historical use of the name East Sea. The video calls for the use of both names alongside each other on international maps.

The Japanese government lodged a protest through diplomatic channels, Chief Cabinet Secretary Yoshihide Suga said at a news conference.