Vice foreign ministers had a "secret duty" to inform their foreign ministers of the clandestine Tokyo-Washington accord that has covered the handling of nuclear arms in Japan since 1960, a former vice foreign minister said Monday.

Ryohei Murata unveiled the details about the secret pact during a telephone interview in which he agreed to give up his anonymity in speaking about the accord, on which Kyodo News reported in late May.

Holding the ministry's top bureaucratic post from 1987 to 1989, Murata, 79, is one of four former vice ministers cited in the May 31 report that said the accord has been controlled by top Foreign Ministry officials and only a handful of prime ministers and foreign ministers were told of it.