The governor of Shimane Prefecture, western Japan, has called on the central government to stand firm in diplomatic negotiations with South Korea to resolve a territorial issue concerning the Takeshima Islands.

South Korea controls the islands in the Sea of Japan. Japan claims them. The Japanese government maintains the islands are an inherent part of Japan's territory. It says South Korea is illegally occupying them.

Japan incorporated the island into Shimane Prefecture on February 22, 1905.

In 2005, the prefecture designated the date as Takeshima Day, and has since held a commemorative ceremony every year in its capital Matsue City.

This year's ceremony was open to members of the public for the first time in four years without coronavirus restrictions. Over 320 people attended, an increase of 130 from last year.

On Thursday, Governor Maruyama Tatsuya noted it has been 70 years since South Korea illegally occupied Takeshima. He said recent moves by South Korea, such as lawmakers setting foot on the islands and defense drills in waters around them, are extremely regrettable.

Maruyama said these actions are aimed at making South Korea's illegal occupation of Takeshima an established fact. He said intergovernmental talks are essential to settle the dispute.

At the event, Cabinet Office Parliamentary Vice-Minister Hiranuma Shojiro pledged the government's utmost efforts in dealing with the issue tenaciously.

Hiranuma said the government will continue conveying Japan's stance firmly and resolutely to South Korea.

He added the government will work hard to enlist support from the international community by promoting a correct understanding of the issue and Japan's position.

South Korea has protested the Takeshima Day event. South Korea calls the Takeshima Islands Dokdo and claims sovereignty over them.

A statement from a South Korean Foreign Ministry spokesperson said on Thursday that Seoul strongly protests Japan's repeated and unjust territorial claims to Dokdo, as demonstrated by the hosting of so-called "Takeshima Day," and urges Japan to immediately abolish the event.

The statement went on to say that Dokdo is undoubtedly an integral part of Korean territory, historically, geographically and by international law. It stated that the Japanese government must promptly abandon its unjust claims to Dokdo and squarely face history in a humble manner.

The South Korean Foreign Ministry also summoned Mibae Taisuke, the deputy chief of mission at the Japanese Embassy in Seoul, and lodged a protest.

In response, Mibae stated that the Takeshima Islands are an integral part of Japanese territory, historically and according to the international law.

In addition, the ministry said South Korean Foreign Minister Cho Tae-yul raised the issue during a meeting with his Japanese counterpart, Kamikawa Yoko, on Wednesday in Brazil. Cho protested over the fact that Shimane Prefecture in western Japan held the annual event and that the Japanese government sent a parliamentary vice-minister to attend it.