South Korea needs close cooperation with Japan, not only with the United States, to better meet the security challenges posed by the Democratic People's Republic of Korea (DPRK), a former top diplomat said here Thursday.

"Close cooperation between South Korea and Japan is vital to deter threats posed by North Korea (DPRK)'s continued development of nuclear programs," former Foreign Minister Yu Myung-hwan told a local forum.

"South Korea and Japan should depend less on the United States and China in shaping the future of East Asia," Yu said, adding the two should play a more active role in contributing to the regional peace and stability.

Longstanding historical disputes between Seoul and Tokyo should not cloud such efforts, the former top diplomat said, especially at a time when the new leadership takes root in both countries.

The remarks, made at the Korea-Japan forum held in central Seoul, came two days after the DPRK conducted a long-threatened nuclear test that ratcheted up military tensions in the region.

The forum was also attended by Japan's former Chief Cabinet Secretary Yohei Kono, whose 1993 statement acknowledged Korean women were forced into sexual slavery during World War II.

Japanese Prime Minister Shinzo Abe, however, has voiced skepticism over the statement and suggested there needs to be a " review" of the Kono statement.