The Foreign Ministry has continued to refuse disclosing minutes of a Japan-U.S. joint committee meeting in 1960, even though the document was submitted to a court and is thus considered publicly accessible, a civic group calling for disclosure said Tuesday.

The document in question contains minutes of the committee's first meeting on June 23, 1960, and simply says that the official minutes "will not be released without mutual agreement" by the Japanese and U.S. governments.

The Joint Committee, established by the Japan-U.S. Security Treaty and Status of Forces Agreement, is a key framework for senior officials to discuss the legal status of U.S. military personnel and their families, and possibly tackle sensitive issues such as the handover of U.S. service members suspected of crimes to Japan.

The ministry turned down the group's requests to make the document public, citing potential diplomatic harm in doing so.

The document also says that "the United States recommended and Japan concurred in the adoption of the following procedures and arrangements."

The document has already been submitted by the state as evidence in a Defense Ministry-linked trial. The lawsuit was filed at the Naha District Court in Okinanawa in March last year.

The group has expressed its alarm over the ministry's refusal to disclose the document, saying the ministry is "at risk of unduly expanding the scope of what is classified as a diplomatic secret."

Displeased by the ministry's decision, the group filed a lawsuit with the Tokyo District Court last December. The state has argued that making the document public without the agreement of the partner country will "pose a big obstacle to diplomatic activities."

The ministry's Status of U.S. Forces Agreement Division has declined comment, as the case is pending in court.