TOKYO (AP) _ An advertisement in the nation's leading financial newspaper attacking Jews has revived concern over a small but virulent strain of anti-Semitism in Japan.

The ad, touting a three-volume book that purports to detail a ''Jewish conspiracy'' to destroy Japan, drew sharp protests from American Jewish leaders.

The controversy spotlights a longstanding Japanese literary genre: bizarre books blaming Jews for everything from the Chernobyl nuclear accident to the rapid appreciation of the yen.

Although such books are generally not believed to reflect widespread public sentiment, the publishers are often mainstream houses, the books are frequently bestsellers and the authors include college teachers and lawmakers.

The popularity of anti-Semitic books worries the Tokyo government, which fears harm to Japan's image abroad. Several years ago, the Foreign Ministry asked publishers to be sensitive to the impression such works can create.

But the books remain common. The third-of-a-page advertisement in Tuesday's editions of the Nihon Keizai Shimbun was for a three-volume work titled ''Hit Japan, Their Last Enemy.''

''You should know the shocking truth of the last few years,'' said the ad, which spoke of a Jewish plot to rule the world. ''Half the human race will be killed and Japan will be enslaved.''

The ad contained a number of vitriolic references to Jews, including suggestions that Judaism involves satanic practices.

In a letter to the newspaper, copies of which were sent to news organizations Thursday, the Los Angeles-based Simon Wiesenthal Center expressed outrage at the ''blatant and outlandish lies'' in the advertisement.

Rabbi Abraham Cooper, the center's associate dean, said he was shocked that a respected newspaper ''would lend its name for a few yen to spread this hateful propaganda.'' He asked for a published apology and urged the paper not to run similar ads in the future.

The newspaper, however, refused to apologize and said it was not its job to censor advertisers' views.

''To protect press freedom, all ads are treated equally,'' spokesman Shigeaki Umeda said Thursday.

It isn't the first time the Nihon Keizai Shimbun has come under criticism for providing a forum for anti-Semitic views. Several years ago, it published an economics primer in comic form that depicted what it called a ''Jewish capitalist.''

Jewish leaders in Japan say the popularity of anti-Semitic literature here reflects widespread ignorance about Judaism. Jewish residents, virtually all foreigners, number only a few thousand in a country of 125 million.

Fred Harris, president of the Tokyo-based Jewish Community of Japan, said he does not think most Japanese are hostile toward Jews. But he said even the existing anti-Semitic sentiment is disturbing. ''It brings back memories of sad days in our history. ... It's hard to know how to combat it,'' he said.

As a racially homogeneous country, Japan has often displayed fear and mistrust of ethnic minorities. Japanese politicians have regularly made remarks that have offended American blacks. In recent months, right-wing groups have put up posters with swastikas saying there are too many foreigners in Japan.

Police also have cracked down on gatherings of some foreigners, closing a section of one park that was a popular spot for Iranians to congregate.