A former senior official at the Foreign Ministry said on a TV talk show Sunday that he had compiled five volumes of documents related to a secret Japan-U.S. nuclear pact and handed them on to his successor.

Kazuhiko Togo, a former head of the ministry's Treaties Bureau, would not reveal the details of the documents, but said the government should come clean with the public about the secret agreement to help clear up discrepancies between the facts and previous government denials that the agreement existed.

Togo served as the head of the Treaties Bureau from July 1998 to August 1999.

The documents, which are said to have been discovered as a result of a ministry investigation, are believed to be linked to a secret pact that was allegedly concluded when the Japan-U.S. Security Treaty was revised in 1960.

The agreement reportedly allowed U.S. warships or aircraft carrying nuclear weapons to make port calls or land on Japanese soil.