The Japanese government on Monday gave a former prime minister a ticking off over a "personal" visit to Iran, where he met President Mahmoud Ahmadinejad and apparently criticised the IAEA.
Yukio Hatoyama, whose short stint in the top job ended in June 2010 after just nine months, was publicly admonished by his own party for comments he reportedly made during the trip claiming the UN's nuclear watchdog was being unfair to Iran.
"The (Japanese) government is taking a consistent position that it would be better if he had not gone (to Iran) at a time like this, even if it is a personal trip," Chief Cabinet Secretary Osamu Fujimura told reporters.
Hatoyama, who has emerged as something of a loose cannon since being forced from office, was already under a cloud for the trip after Foreign Minister Koichiro Gemba expressed concerns that it could undermine international action against Tehran.
The West believes Iran is developing nuclear weapons, but Tehran insists its atomic programme is peaceful and purely for energy.
Ahmadinejad stressed to Hatoyama on Sunday that Tehran opposes nuclear weapons, his official website reported.
"The Islamic Republic of Iran is fundamentally opposed to the atomic bomb and weapons of mass destruction," Ahmadinejad told Hatoyama.
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"Iran and Japan can exert a common effort to create a world without atomic weapons... Difficult but humanitarian efforts will win in the end."
The presidential office also quoted Hatoyama as criticising the UN nuclear watchdog, the International Atomic Energy Agency, for being unfair, local media said.
Fujimura said Monday that Hatoyama's reported comments were at odds with Tokyo's position.
"Japan respects the IAEA's role in solving nuclear-related issues," Fujimura said. "Japan is asking Iran to thoroughly cooperate with the IAEA so that it can solve pending issues over its nuclear programme."
Talks between Iran and the five permanent UN Security Council members and Germany are due to start Friday, in a country yet to be agreed.
Hatoyama, the millionaire scion of an influential family, swept his Democratic Party of Japan (DPJ) to a stunning election victory in September 2009, ending more than half a century of almost unbroken conservative rule.
But his short-lived premiership was blighted by a reputation for crippling indecision.
Despite his status as a senior adviser to the DPJ, he has struggled to find a role in public life since joining the ever-swelling ranks of former Japanese prime ministers.