Updated

A Japanese consular official who committed suicide in Shanghai in 2004 was blackmailed by Chinese intelligence agents who set him up with a woman in an attempt to obtain classified information, Japan's foreign minister said Saturday.

The Foreign Ministry had previously said only the official's death was a result of an unspecified diplomatic incident with a Chinese intelligence official.

But Foreign Minister Taro Aso said on Saturday that the official committed suicide in May 2004 and left a note.

"They approached him, offering to arrange a sexy woman for him," Aso said in a speech. "Then he was blackmailed to give away secret codes for classified information. It is clear from a suicide note he left."

The diplomat was asked to provide numbers needed to decipher secret codes but chose to kill himself instead because he could not sell out his country, Aso said.

Amid media speculation about intelligence operations featuring "honey traps" targeting Japanese diplomats in China, Prime Minister Junichiro Koizumi last month warned diplomats of "seductions or attempts to steal secrets."

The Foreign Ministry also urged embassy and consulate workers worldwide to be on their guard and ordered all staffers in China to use extra caution against spy activities.

"Most diplomats aren't so good looking (and) they should be trained to be cautious when they're approached by women," Aso said, according to the Kyodo News Agency.

The incident prompted Japan last month to accuse China of violating the Vienna convention on diplomatic relations that guarantees the inviolability of diplomats.

Beijing in turn issued a harsh protest over Tokyo's suggestion that the actions of a Chinese spy might have forced the consular official to take his life.

Kyodo said Aso planned to take a decisive action against China over the issue. It did not elaborate.

Relations between Tokyo and Beijing have been battered in recent months by a string of disputes.

The two sides have argued over Koizumi's visits to a shrine that honors Japan's war dead including convicted war criminals, conflicting interpretations of Japan's wartime atrocities, as well as undersea gas deposits in the East China Sea.