The defense ministers of Japan and South Korea are planning to hold talks, in Singapore in early June, for the first time in 3½ years, a source familiar with the matter has said.

Defense Minister Yasukazu Hamada and his South Korean counterpart Lee Jong-sup are expected to discuss South Korea's alleged fire-control radar lock-on of a Self-Defense Forces plane in 2018, an outstanding issue for the two countries that have seen signs of rapprochement recently, the source said Tuesday.

The meeting is being arranged on the fringes of a three-day Asia Security Summit, known as the Shangri-La Dialogue, in the Southeast Asian city-state from June 2.