Three Japanese historians arrived on South Korean-controlled Dokdo islands on Thursday in an unusually publicized visit that did not sit well with Japanese officials.

Norio Kuboi, one of the Japanese historians, said the visit’s aim was to carry out on-site research on the disputed islets in the Sea of Japan, known as Takeshima islets in Japan. The group added the trip was part of its investigation into the circumstances of the islets’ 1905 incorporation into Shimane Prefecture as Japanese territory.

Another member was barred from joining the trip after allegedly contesting Seoul’s sovereignty over the islets.

“We confirmed that South Korean residents are living on Takeshima, and that the islets are being guarded. It is clear that South Korea is in a position of being able to claim sovereignty over the islets,” Kuboi told Japan Times by telephone.

The Japanese Consulate in Busan earlier this week called on the group to cancel the trip. The Foreign Ministry in Tokyo calls on Japanese to refrain from visiting Takeshima, saying such visits “serve to recognize South Korea jurisdiction over the islands,” the same paper reports.