The government plans to release new evidence it says proves its claim that a South Korean warship locked its fire-control radar on a Japanese plane, a government source said Saturday.
It is considering making public an audio recording from the Japanese Maritime Self-Defense Force patrol plane that it claims was targeted over the Sea of Japan on Dec. 20, the source said.
Tokyo released in late December video footage of the alleged incident in which it says the vessel engaged a radar system that measures how far away a target is and its direction of travel.
South Korea maintains Japan has presented no definitive proof to back its claim.
The intensity of radio waves used by the radar tend to be constant and powerful, and the footage showed an MSDF crew member remarking on the Japanese plane's systems picking up an "extremely strong" reading.
Japan will decide on whether to release the audio recording after Defense Minister Takeshi Iwaya returns from the United States on Sunday, according to the source.
"We should avoid any misunderstanding among Japanese citizens and the international community. We have to explain what happened," Iwaya told reporters while visiting Hawaii.
Japanese and South Korean officials have held talks but so far failed to overcome their differences.