TOKYO, April 21 (Xinhua) -- Japan's prime minister Shinzo Abe reiterated his apology over wartime sex slavery in a recent interview with the U.S. magazine Newsweek, Kyodo News said Saturday.

    "As Japan's prime minister, I am extremely sorry that they were made to endure such pain. We feel responsible over the situation in which the women had to exist as 'comfort women' and endure such hardship," the premier was quoted as saying in the interview, before his scheduled trip to the United States next week.

    Abe said Tuesday that "we must always be humble (in dealing with) our history and constantly give profound thought on our responsibility" in the interview conducted in Tokyo.

    According to the report, the prime minister also repeated the vow to stick to a 1993 statement made by the then Chief Cabinet Secretary Yohei Kono, who officially acknowledged and apologized over the fact that Japan forced women from other Asian countries to be sex slaves for its soldiers during World War II.

    The wartime sex slavery issue has drawn international attention since Abe said recently that there are no documents to prove the Japanese military physically coerced women to provide sex for its soldiers during World War II.

    An estimated 200,000 women were forced to serve as sex slaves for Japanese forces during World War II, most of whom came from countries invaded by Japan at the time.