The Japanese government has been discussing how to enhance methods of interception in the wake of China's increasing maritime and air patrols in the waters off the disputed Diaoyu Islands in the East China Sea, and Japan might order its F-15J fighter jets to fire warning shots against Chinese surveillance planes, local media reported on Wednesday.
A Chinese foreign ministry spokesman said in a response that China "remains vigilant against attempts to escalate the tensions."
"Patrols conducted by Chinese planes and vessels in waters off the Diaoyu Islands, which are China's inherent territory, are normal official duties to exercise China's jurisdiction rights. China opposes any infringement on its sovereignty over the islands committed by Japanese aircraft or vessels," Hong Lei told reporters at a regular press briefing.
China's Ministry of National Defense also said last month that China's military has been closely monitoring the activities of the Japan Air Self-Defense Force near the Diaoyu Islands.
A move by the Japanese government to "purchase" three of the five uninhabited islands from "Japanese private owners" in September last year triggered the latest round of confrontations between China and Japan.
China's State Oceanic Administration has since then intensified its regular patrols of the waters off the Diaoyu Islands by sending marine surveillance ships and planes.
Japan's Sankei Shimbun newspaper said on Wednesday that the Japanese government was considering strengthening confrontation measures with China including firing warning shots with tracer bullets against Chinese planes.
But a spokesperson from the Japanese defense ministry contacted by the Global Times said the ministry "hasn't come up with such a detailed plan," and declined to comment on China's surveillance activities.
Whether a warning shot by the Japan Air Self-Defense Force would go against its pacifist constitution, which renounces the threat or use of force as a means of settling international disputes, remains under debate.
A retired Chinese air force pilot, who declined to be named, told the Global Times that not all the types of tracer bullets would cause damage to planes, but in the case of the Diaoyu Islands, any warning shots by Japan would be dangerous and would definitely be regarded as hostile aggression or a declaration of war.
A Tokyo-based observer said it is "illegal" for Japan to attack first. "It only has the right to fire back when it comes under attack," the observer said.
The controversial move came on the same day as the Japanese defense ministry announced its plans to spend an extra $2.1 billion on procuring PAC-3 surface-to-air anti-ballistic missile systems, upgrading four existing F-15 fighter jets, and purchasing a number of military helicopters.
This plan is separate from a request for a rise in the military budget for the next fiscal year which Prime Minister Shinzo Abe's ruling Liberal Democratic Party called for on Tuesday.
The increase in military spending is said to be part of broader economic stimulus measures set by the ambitious Abe cabinet.
Meanwhile, Japan has been in close communication with the US on its moves regarding the island disputes with China.
"Any attempts by Japan to draw in a third party to confront China over the Diaoyu Islands issue will be in vain," Hong said.
Ni Feng, deputy head of the Institute of American Studies at the Chinese Academy of Social Sciences, told the Global Times that the bottom line for the US is that it is "not being dragged by Japan into war with China," although Washington has repeatedly told Tokyo that the US-Japan defense treaty applies to any incidents related to the Diaoyu Islands.
Agencies contributed to this story