This photo taken on Aug 23, 2022 shows a US military Osprey aircraft at the US Marine Corps Air Station Futenma in the center of the city of Ginowan, Okinawa prefecture, Japan. (PHOTO / AFP)

TOKYO - Japan's Okinawa prefectural government on Monday rejected a high court order to approve a revised plan for a key US base relocation within the southernmost prefecture, local media reported.

Okinawa will appeal the high court ruling to the Supreme Court, Kyodo news reported, citing a prefectural government official.

Okinawa Governor Denny Tamaki issued a statement saying that the high court ruling, issued on Wednesday, has "various problems" and that it was "difficult" for him to approve the modified plan when many Okinawa residents are against the relocation of the Futenma base within the prefecture.

The controversial project aims to relocate the US Marine Corps' Futenma air base in Ginowan to the Henoko coastal area in Nago, which is also in Okinawa

Meanwhile, Japanese Prime Minister Fumio Kishida told reporters in Tokyo that Tamaki's failure to comply with the judicial judgment was "regrettable," Kyodo News said.

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Following Tamaki's decision, the central government is expected to approve the design change by proxy as early as Thursday, in its first-ever proxy execution, the report said.

The Defense Ministry's Okinawa Defense Bureau will then begin the ground improvement work in mid-January or later, it said.

The Naha branch of the Fukuoka High Court on Wednesday ordered Tamaki to approve the central government's design change for planned ground improvement work under the US base relocation project.

The controversial project aims to relocate the US Marine Corps' Futenma air base in Ginowan to the Henoko coastal area in Nago, which is also in Okinawa.

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Earlier in September, Tamaki told a United Nations Human Rights Council meeting in Geneva that the concentration of US military bases in Okinawa threatens peace, noting that the Japanese government is forcibly filling in precious sea areas to build a new US military base, regardless of the opinions of local residents.

The governor has also, on multiple occasions, expressed concerns over excessive levels of toxic per- and polyfluoroalkyl substances detected in the water around US military bases in Japan.

The island of Okinawa hosts 70 percent of all the US military bases in Japan while accounting for only 0.6 percent of the country's total land area. More than 70 percent of local residents opposed the US military base construction on the Henoko landfill, showed a 2019 Okinawa Prefecture voting results.