TOKYO - Japan released video footage Friday it said proved a South Korean warship locked its fire-control radar onto a Japanese warplane off the northeastern coast in the latest move of an escalating row between the Asian neighbours.

The Defence Ministry's just over 13-minute footage, filmed from the P-1 patrol aircraft, contained voices of Japanese crewmembers asking the destroyer for clarification but getting no response.

Japan alleged that the South Korean destroyer repeatedly locked its targeting radar on the Japanese aircraft Dec. 21 inside of Japan's exclusive economic waters off the Noto Peninsula. A lock with fire-control radar is considered a hostile act and only one step away from actual firing.

South Korea has denied the allegation, saying its warship used an optical camera while rescuing a North Korean fishing boat in distress. Seoul's Defence Ministry expressed "deep regret and concern" over Japan's release of the video a day after the countries' military officials held a video conference to resolve what Seoul described Tokyo's "misunderstanding."

Relations between Japan and South Korea have degraded to their worst in recent years over compensation issues related to sexual abuse of "comfort women" and Korean forced labour 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 via three frequencies but the destroyer stayed silent. The voice grew slightly tense as the crew kept calling.

The video and published on the Tokyo ministry's website starts showing the grey destroyer sailing near a pair of rubber boats and a North Korean vessel. About six minutes later, one of the crewmembers can be heard saying: "She is emitting FC," and that it was coming from the destroyer. The pilot moves away from the warship.

The video shows the aircraft detecting more signals from the radar on the South Korean destroyer, but the pilot confirms that a gun is not pointed to their aircraft.

Choi Hyun-soo, South Korea's Defence Ministry spokeswoman, said the footage provided no proof of what Japan said had happened but showed a Japanese aircraft conducting a "threatening low-altitude flight" over a South Korean warship at a rescue operation of a drifting North Korean boat.

"The video material made public by Japan contains only footage of the Japanese patrol plane circling above the surface of the sea and the (audio) conversation between the pilots and it cannot by common sense be regarded as objective evidence supporting the Japanese claims," Choi said. She reiterated that the destroyer Gwanggaeto was in normal rescue operation. "There's no change to the fact that our military did not operate tracking radar on a Japanese patrol plane."

Defence Minister Takeshi Iwaya told reporters earlier Friday that he decided to release the footage and data as objective evidence to let the people in and outside Japan know that the Japanese Self-Defence 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."

___

AP writer Kim Tong-hyung contributed to this report from Seoul, South Korea.

___

Follow Mari Yamaguchi on Twitter at https://www.twitter.com/mariyamaguchi

News from © The Associated Press, 2018