Tokyo: Japan is to investigate a report that it considered arming itself with nuclear weapons in the late 1960s despite its pacifist vow to shun them, a senior government official said Monday.

Public broadcaster NHK reported that Japan secretly considered going nuclear and sought advice from what was then West Germany in meetings with foreign ministry officials in February 1969 in the Japanese resort of Hakone.

The report cited confidential West German foreign ministry documents.

Japanese Foreign Minister Seiji Maehara has ordered his ministry to investigate the report, State Secretary for Foreign Affairs Takeaki Matsumoto told a news conference.

Chief Cabinet Secretary Yoshito Sengoku, the top government spokesman, said details of the allegation needed to be clarified, including which “chain of command” was responsible for such talks.

Japan, the only nation to be attacked with nuclear weapons, was hit with two atomic bombs by the United States in the closing days of World War II.

It has maintained its policy against the possession, production and presence of nuclear weapons in its territory since 1967.

The non-nuclear principles were first declared by then-prime minister Eisaku Sato in 1967 and a resolution to abide by them was adopted in parliament in 1971.

In the secret talks, the Japanese side said it had sufficient technology to produce nuclear weapons to guard itself against the nuclearisation of the region after China conducted a nuclear test in 1964, NHK reported.

But Germany, divided after World War II, responded that it would be difficult to cooperate with any Japanese nuclear ambitions.