Japan has demanded an immediate halt to a South Korean company's daily boat tour program to the Dokdo islets.

Deputy Chief Cabinet Secretary Masaaki Yamazaki issued the demand Wednesday, saying his government cannot tolerate such action.

Yamazaki's remarks came after Dokdo Tour Marine Co. started daily boat tours on Wednesday to the volcanic islets claimed by both South Korea and Japan.

Seoul maintains that the islets belong to South Korea based on precedents of history, geography and international law, and effectively controls the islets with a small contingent of coast guards.

Japan laid claim to the volcanic outcroppings only after colonizing the Korean Peninsula in the early 20th century.