At 2:03 p.m. local time (05:03 GMT), a Japanese Maritime Self-Defence Force patrol plane flew close to the South Korean Navy warship at an attitude of 60 to 70 meters (197 to 229 feet), near the Jeju Island, the Yonhap news agency specified.
"[South Korean] Defence Minister Jeong Kyeong-doo, along with the Joint Chiefs of Staff, is working on this issue at this point", the unnamed official told Yonhap.
Suh Wook, the chief director of operations at the Joint Chiefs of Staff, condemned the Japanese aircraft's flight as a "provocative act."
"This low-altitude, close-range flight toward the ship of a partner country again today is a clearly provocative act, and we cannot help but doubt Japan's intent, and [we] strongly condemn this", he said at a press conference, as quoted by Yonhap.
He pledged that the South Korean military would "strongly" respond if such an incident repeated again.
According to the Japanese side, on December 20, a South Korean destroyer purposefully directed its fire-control radar at Japanese Maritime Self-Defence Force patrol plane in the Sea of Japan. Seoul responded by saying that it had been rescuing a North Korean fishing ship in distress, using an optical camera and not the radar.