The government has asked a county in Maryland not to teach public school students the South Korean name for the sea separating Japan and the Korean Peninsula, a government official said in Tokyo.
The government told the county that the Sea of Japan is the only internationally established name for the waters, but the county has not changed its policy, the official said Wednesday, declining to identify it.
South Korea calls the waters the East Sea.
According to a report by South Korea's Yonhap news agency, Anne Arundel County instructed public schools to teach students the existence of a dispute over the name of the waters if maps used in class only carry the name Sea of Japan.
The county took the measure in reaction to a call by a Virginia-based group of Koreans, the Voice of Korean Americans, that says the Sea of Japan monicker is a result of Japan's 1910-45 colonial rule of the Korean Peninsula.
Anne Arundel is the first U.S. county to issue such an instruction to public schools, according to the group.
The U.S. government said last year it would continue calling the waters the Sea of Japan.
Every year, South and North Korea press their case for using the East Sea appellation at the U.N. Conference on the Standardization of Geographical Names, while Tokyo says it is groundless to claim the Sea of Japan name is a vestige of its colonial rule, according to U.N. diplomatic sources.