Earlier on Sunday, the Yonhap news agency reported that South Korean forces were conducting two-day exercises in the area of the islands. According to the agency, naval, air and land forces are involved in the exercises, and there is no information on their strength yet.
"These exercises are unacceptable. It is regretful, and we strongly call for cancellation of the manoeuvres," the protest note says, as quoted by the agency's source.
The protest was sent via diplomatic channels. Tokyo insisted that the islands belonged to Japan.
The Liancourt Rocks islands, also referred to as Dokdo by South Korea and Takeshima by Japan, lie almost equidistant from the two states. They have been administered by Seoul since 1954, a claim Japan disputes. Tokyo has suggested that Seoul should present the issue to the International Court of Justice. However, South Korea believes there is no dispute over the islands and considers them to be its territory historically, geographically and legally.