BEIJING (Yonhap News) -- South Korea plans to forge closer diplomatic cooperation with China to jointly counter reinforced Japanese moves to lay claims to Seoul's easternmost islets of Dokdo, the South Korean ambassador in Beijing said Saturday.

Ambassador Kwon Young-se made the remarks at an annual parliamentary audit on the embassy as Japan is stepping up its global PR campaign for its assertions of sovereignty over Dokdo.

China is also in an acute territorial dispute with Japan over a set of islands in the East China Sea, known as Diaoyu in China and Senkaku in Japan.

"With regard to the issue of Dokdo and other history-related matters, we will strengthen our diplomatic efforts to secure a closer cooperative system with China," Kwon said during the audit session. "As part of our efforts, we will actively explain our stance about the issues to relevant Chinese officials."

Dokdo, which lies closer to South Korea in the body of water between the Korean Peninsula and Japan, has long been a thorn in relations between South Korea and Japan.

South Korea keeps a small police detachment on the islets, effectively contoling them.

This week, Japan's foreign ministry posted two YouTube videos as part of its global campaign to reinforce its claim to Dokdo.

South Korea lodged a formal protest with Japan.

"The Japanese government should realize that such an ahistorical and anachronistic provocation is one of the most crucial factors hindering advances in the ROK(South Korea)-Japan relations," Seoul's foreign ministry spokesman Cho Tai-young said.

Cho urged Japan to abandon its "vain territorial claims to Dokdo."

South Korea has rejected Japan's claim to Dokdo as nonsense because it regained its independence from Japanese colonial rule and reclaimed sovereignty over its territories, including Dokdo and many other islands around the Korean Peninsula.