Japan's government today vowed to stick to its ban on nuclear arms after a probe showed its predecessors may have turned a blind eye to breaches, but said ties with security ally Washington would not be affected.
The United States had urged Japan not to let the investigation into past "secret pacts" over nuclear weapons damage their relationship, which has been shaken by a feud over the relocation of a US Marine base on the island of Okinawa.
"This should not affect US-Japan relations, at the same time, there is no need to change the three non-nuclear principles," prime minister Yukio Hatoyama told reporters, referring to Japan's policy of not possessing or producing atomic weapons, or allowing them into the country.
A panel of experts commissioned by foreign minister Katsuya Okada examined thousands of documents over a period of months, concluding that there was a tacit agreement between Tokyo and Washington that may have allowed U.S. vessels carrying nuclear weapons to enter Japanese ports without prior discussion.
Mr Okada touted the report, which contradicted previous governments' denials, as a victory for democracy months ahead of an upper house election the ruling Democratic Party must win in order to avoid policy deadlock.
"Making the facts clear is the very basis of democracy," he told reporters.
In Washington, State Department spokesman PJ Crowley said the probe was a Japanese government matter that would not significantly affect cooperation between Japan and the United States.
"We understand the special sentiment of the Japanese people with regard to nuclear weapons," Mr Crowley said, adding that the United States would honor its security commitments to Japan.
The 6-month-old government's handling of ties with Washington has weighed on voter support, adding to falls sparked by a series of financial scandals involving ruling party lawmakers.
During a visit to Tokyo in October, US defense secretary Robert Gates urged Japanese Defense Minister Toshimi Kitazawa to ensure the investigation of the pacts did not damage the US-Japan relationship.
In calling for a world free of nuclear weapons, Japan often emphasises its status as the only country to have suffered nuclear attacks.
But Tokyo also benefits from the shelter of the US nuclear umbrella, and many in Japan would be reluctant to see the United States' nuclear deterrent significantly weakened in the face of a resurgent China and threats from North Korea.
Mr Okada said he did not envisage the United States bringing nuclear weapons to Japan after a 1991 change in policy by then US president George HW Bush saw them removed from ships. He did not specify how Japan would deal with any threat of nuclear attack in the future.
Reuters