Tokyo in 1971 asked Taipei to refrain from pressing its claim to the Senkaku Islands in return for backing Taiwan's efforts to keep its seat at the United Nations, according to Japanese diplomatic records declassified on Thursday.

Taiwan responded that it would attempt to "cool down" issues related to the islands, the documents show. The islets in the East China Sea are administered by Japan but claimed by China and Taiwan, which call them Diaoyu and Tiaoyutai, respectively.

Former Foreign Minister Kiichi Aichi made the request at a meeting in Tokyo with Taiwan's ambassador to the United States when Taipei was on the verge of losing its U.N. seat.