TOKYO — Japan's biggest newspaper apologized in print Friday for using the term "sex slaves" in its English-language edition to describe Asian women forced into Japanese military-run brothels during World War II.

The conservative Yomiuri said in articles in English and Japanese that it was inappropriate to have used the phrase and others implying the women were coerced to provide sex. The newspaper identified 97 articles, including 85 of its own, with "sex slaves" or similar expressions between 1992 and 2013.

It said non-Japanese people have difficulty understanding the term "comfort women," used in Japan to describe the women, so its English-language edition added explanations improperly suggesting that "coercion by the Japanese government or the army was an objective fact."

Yomiuri also publishes English-language newspaper The Japan News (formerly called The Daily Yomiuri), which also issued an apology.

"The Japan News apologizes for having used these misleading expressions and will add a note stating that they were inappropriate to all the articles in question in our database," the apology reads.

"The expression 'comfort women' was difficult to understand for non-Japanese who did not have knowledge of the subject. Therefore the [newspaper], based on an inaccurate perception and using foreign news agencies' reports as reference, added such explanations as 'women who were forced into sexual slavery' that did not appear in The Yomiuri Shimbun's original stories."

Prime Minister Shinzo Abe, other conservative lawmakers and activists have a long-running campaign against the term "sex slaves," maintaining the women weren't forced.

A government investigation in the early 1990s concluded that many of the women "were recruited against their own will" and "lived in misery at comfort stations under a coercive atmosphere," according to an apology issued by then-Chief Cabinet Secretary Yohei Kono.

It said in many cases the women were recruited by coaxing and coercion, and that government and military officials were often directly involved.

The investigation found no proof in existing official documents, and conservatives have used that to argue their case.

Abe, who took office in December 2012, hoped to revise Kono's 1993 apology, but later promised not to do so following protests from South Korea and elsewhere.

The efforts to deny coercion have soured relations with South Korea, where some of the women came from. Historians say tens of thousands of women from across Asia were used in military brothels. They say most Japanese women in the brothels were prostitutes by profession, while many others were kidnapped.

In August, the liberal-leaning The Asahi Shimbun newspaper apologized for having quoted a person whose account of abducting Korean women to become sex slaves turned out to be a fabrication. Its apology and retraction of articles from the 1990s containing the comments led to extensive criticism of The Asahi by conservative lawmakers and media.

But Chief Cabinet Secretary Yoshihide Suga told parliament that officials didn't take the person's account seriously, and it did not affect the results of Japan's investigation or its apology.

Additional reporting by Mashable