Well, Israeli Prime Minister Olmert told Japanese Prime Minister Fukuda that the “Box on the Euphrates” asked for it, “Japanese government sources” leaked the contents of the meeting to the Asahi Shimbun, and Asahi translated it as “nuclear-related.” Maybe he said “reactor”. I dunno:
Japanese government sources said over the weekend that the Israeli leader, Ehud Olmert, briefed Prime Minister Yasuo Fukuda about the attack during summit talks in Tokyo on Feb. 27.
[snip]
According to the sources, Olmert told Fukuda that the site was a nuclear-related facility that was under construction with know-how and assistance from North Korean technicians dispatched by Pyongyang.
Olmert also said Israel remains concerned about the issue of nuclear proliferation by North Korea and sought greater information sharing with Tokyo through expanded dialogue on the issue.
Japanese government officials expressed differing views on how to interpret Olmert’s statement.
“While we cannot confirm the facts, the fact that such an assertion was made at an official occasion such as a summit meeting is significant, making it highly credible,” said one high-ranking Foreign Ministry official.
Another Foreign Ministry official pointed out, however, that the Israeli leader “may have only presented facts that were favorable for the Israeli side.”
This is the English summary. The Japanese version is here. I am also posting the full-text in Japanese in the comments because readers MTC and Robot Economist have been kind enough to collaborate on short-translations from Japanese that are of interest to the community.
Check out their fine discussion about the Sankei article on Japanese nuclear weapons.