South Korea's defense chief has apologized over the description of the country's easternmost islets of Dokdo as a disputed territory in the military's newly published educational material for troops.

On Thursday, the ministry began recalling the basic educational material after President Yoon Suk Yeol instructed immediate corrections. The material had listed Dokdo among disputes between major countries around the Korean Peninsula, such as China, Russia and Japan.

"As I made the final decision on its publication, all responsibility lies with me," Defense Minister Shin Won-sik told reporters on Thursday. "I should have looked into it in detail before it was published, and I apologized (to the president) for not doing so."

The material had said such countries project their military power abroad for their national interests and military conflicts could occur at any time as territorial disputes, including the Diaoyudao/Senkaku Islands, the Kuril Islands and the "Dokdo issue," are ongoing.

Japan and China have been in a dispute over the Diaoyudao Islands, known as the Senkaku Islands in Japan, while Japan and Russia have been at odds over the Kuril Islands known in Japan as the Northern Territories.

Seoul has rejected the existence of any territorial dispute over Dokdo, calling the set of rocky islets an integral part of South Korean territory in terms of history, geography and international law.

Separately, the Navy staged regular defense drills around Dokdo earlier this month, according to a military official.

The latest exercise took place in mid-December at a similar scale as the last one in June, with Navy and Coast Guard ships and without Marines landing on the islets, according to the official.

It marked the fourth such exercise under the Yoon administration.

South Korea launched the Dokdo drills in 1986 and has conducted them twice a year since 2003. (Yonhap)