South Korea on Thursday began a two-day regular naval and air exercise near two islets it controls in the Sea of Japan that are claimed by Tokyo, the South Korean Navy said.
The South's military conducts exercises around the rocky outcroppings, known as Dokdo in South Korea and Takeshima in Japan, roughly twice a year. Its navy said the country's airforce is also taking part, but provided few details.
The exercise, which ends Friday, was expected to involve five to six vessels and four to five aircraft, according to Yonhap news agency.
A similar drill was last held in June with six warships and seven aircraft, drawing a diplomatic protest from Japan.
The two islets and small reefs around them have a combined area of 0.21 square km and are situated roughly equidistant from the Korean Peninsula and Honshu.
South Korea took effective control of the islets in 1954, when it dispatched a permanent battalion there.