The poor state of Tokyo's ties with Seoul were on full display in Japan's annual defense report released Friday, with the government effectively downgrading South Korea's status as a top security cooperation partner.

In a chapter explaining Japan's security cooperation with countries other than its most important ally, the United States, South Korea is mentioned fourth, down from second in the previous white paper, after Australia, India and the Association of Southeast Asian Nations.

Japanese officials did not publicly state that the change in the order is a lowering of South Korea's standing, but a Defense Ministry source has said, "In effect, it means a downgrade."