In this image made from video released Friday, Dec. 28, 2018, by the Japan Maritime Self-Defence Force, a South Korean naval warship is seen as it allegedly locks its fire-control radar on a Japanese warplane Friday, Dec. 21, 2018, in the disputed waters north of Japan Image Credit: AP

TOKYO: Japan released video footage on Friday to prove that a South Korean warship allegedly locked its fire-control radar onto a Japanese warplane off the country's northern coast, the latest move in an escalating row between the two Asian neighbors.

The Defense Ministry's just over 13-minute footage, filmed from the P-1 patrol aircraft and published on its website, contained Japanese crewmembers asking the destroyer for clarification but getting no response.

Japan alleged that last Friday a South Korean destroyer repeatedly locked its targeting radar on the Japanese aircraft inside of Japan's exclusive economic waters off the Noto Peninsula.

A lock with a fire-control radar is considered a hostile act and only one step away from actual firing.

Relations between Japan and South Korea have degraded to their worst in recent years over compensation issues related to Japanese atrocities such as sexual abuse of "comfort women" and Korean forced labor during Japan's colonial rule of the Korean Peninsula from 1910 through 1945. The radar flap has added to the strain.

"Korea South Naval Ship, Hull Number 971, this is Japan Navy. We observed that your FC antenna is directed to us. What is the purpose of your act, over?" a crewmember asked the destroyer in English several times using three different frequencies but the destroyer remained silent. The voice grew slightly tense as the crew kept calling.

The video starts showing the gray destroyer sailing near a North Korean vessel. About six minutes later, one of the crewmembers can be heard saying: "FC detected" and that it was coming from the destroyer.

Seoul has denied the allegation, saying its warship used an optical camera while rescuing a North Korean fishing boat in distress.

Defense Minister Takeshi Iwaya told reporters earlier Friday that he decided to release the footage and data to let the people in and outside Japan know that the Japanese Self-Defense Force operated appropriately.

"It is most important that an incident like this should never be repeated between Japan and South Korea," Iwaya said, adding that relations between the two sides are crucial for regional national security. "Even though difficult issues remain between Japan and South Korea," he said, "I hope to overcome those problems and push forward our mutual understanding and exchange between our two militaries."