The radar-lock issue reportedly relating to two incidents Jan. 19 and Jan. 30 has now taken the center stage in the worsening territorial dispute over the uninhabited, Japanese-controlled Senkaku Islands in the East China Sea, which China also claims, calling the territory Diaoyu Islands.
On Thursday, Japanese Defense Minister Itsunori Onodera told a parliamentary committee China's use of the weapons-guiding radar on the Japanese Maritime Self-Defense Force vessel amounted to a "threat of military force" under the United Nations Charter, while calling for a dialogue to prevent a recurrence of such incidents.
Japan says the incident occurred Jan. 30 and has already lodged a protest with China. The Japanese Defense Ministry also said a Chinese frigate directed the same kind of radar at a Japanese military helicopter on Jan. 19, and that in both incidents, the Chinese ships eventually turned off their radar without firing a shot.
Referring to the Jan. 30 incident, the Chinese Defense Ministry said Friday its naval ship found itself being closely followed and monitored by JSDF destroyer Yudachi while conducting routine training in "relevant waters in the East China Sea."
"The radars on the Chinese naval ship kept normal observation and alert, and fire control radar was not used. Therefore, the Japanese side's remarks were against the facts," the ministry said, adding Japanese warships and airplanes close-in monitoring and surveillance of China's naval ships and airplanes "is the root cause to air and maritime safety issues between China and Japan."
The ministry said Japan has "repeatedly spread false accusations which distorted facts and defamed Chinese military's normal combat readiness training," and that this time "without verifying related facts with the Chinese side, Japan unilaterally released untrue information to the media and senior Japanese government officials made irresponsible remarks."
Responding, Japanese Foreign Minister Fumio Kishida said Friday Japan has replied "that we can never accept the Chinese explanation that (Japan's account of the incident) does not match facts" and called for "a sincere response from them," Kyodo News reported.
Meanwhile, Chinese Foreign Ministry spokeswoman Hua Chunying on Thursday, for the first time since the issue surfaced, said Chinese authorities were verifying and investigating the incident, but also accused Japan of creating tension and tarnishing China's image, the official Xinhua News Agency reported.
She said Japan's efforts to ratchet up tension ran against efforts to improve Sino-Japanese ties and that China wishes to solve and manage problems through talks.
U.S. State Department spokeswoman Victoria Nuland has said actions such as the reported lock-on incident could escalate tensions, increase the risk of a miscalculation and undermine peace and stability in the region.
In recent weeks, there have been a number of other maritime incidents, some of which even led Japan to scramble its fighter jets.
Although the United States has refused to take sides, the islands are seen as coming under its mutual security treaty with Japan.