The body found in a capsized boat in the waters of the disputed Senkaku Islands has been confirmed to be of Taiwanese nationality, while the remaining six crew members, all Indonesians, remain missing, Jakarta said late on Tuesday night.

“The search and rescue operations are still ongoing to find the crew of the Taiwan-flagged Xin Chang Fa ship. One body found yesterday has been identified as the Taiwanese captain of the ship based on fingerprint data,” said Judha Nugraha, the Foreign Ministry’s citizen protection director.

The capsized ship, believed to be carrying seven people, was found on Sunday afternoon drifting in the waters north of the Japanese-administered Senkaku Islands, a grouping of three uninhabited islands that China also claims.

It remains unclear how the boat was overturned, though Taiwan has confirmed via a statement on Monday that the ship was one of its registered fishing boats.

“The Indonesian Embassy in Tokyo and the Indonesian Economic and Trade Office [KDEI] in Taipei continue to coordinate with the relevant authorities to immediately find the six Indonesian crew members,” Judha said.

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Both Taiwanese and Japanese coast guards have dispatched their ships for the search and rescue missions, as Foreign Minister Retno LP Marsudi on Monday requested more ships and aircraft to be deployed for the search. Currently, at least four patrol ships have been deployed.

The Senkaku Islands, currently under Japanese administration, are in dispute over a claim by China, which refers to the island group as Diaoyu. Although uninhibited, the geographic location of the islands lies on important sea lines of communication (SLOC) in the East China Sea.

The United Nations Economic Commission for Asia and the Far East in 1969 also marked the area as potentially being “one of the most prolific reservoirs in the world”.

The disagreement surrounding the islands’ territorial sovereignty had soured China-Japan relations for decades.