South Korea's defense chief has said his country is willing to "normalize" security cooperation with Japan, amid signs of a thaw in bilateral ties frayed over wartime issues.

"We are ready to engage in serious dialogue with Japan," South Korean Defense Minister Lee Jong-sup said in a speech Sunday at the annual Shangri-La Dialogue security summit in Singapore, with his Japanese counterpart, Nobuo Kishi, also in attendance.

There have been recent signs of improvement in bilateral ties under the new South Korean administration of President Yoon Suk-yeol who took office in May.