In an annual Defense Ministry paper adopted on Tuesday by Prime Minister Yoshihide Suga's Cabinet, Japan's government expressed alarm about China and its growing military assertiveness in the region.

The paper, detailing the most pressing military threats to the country, singled out to the tussle over Taiwan in more direct terms than ever before.

''Stabilizing the Taiwan situation is important for Japan's national security and stability of the international community,'' the Japanese government said. ''We need to pay close attention with a sense of crisis more than ever before.''

China considers Taiwan part of its territory, and in recent years it has ramped up diplomatic, military and economic pressure on the self-governed island. It all comes as Beijing has also exerted pressure on Hong Kong and increased its presence on the South China Sea.

"The overall military balance between China and Taiwan is tilting to China's favor, and the gap appears to be growing year by year," the Japanese document said.

Japan eyes China-US rivalry

Japan, like the US and most major nations, does not formally recognize Taiwan as a state — China does not deal with countries who do — but does engage with and support the island's leadership through nongovernmental channels.

But, as Chinese economic and military power increases, particularly at sea, questions about how long the US and its allies can prop up the rival government in Taipei have gathered volume.

The US has increased its military support for Taiwan recently, including dispatching warships to the Taiwan Strait and arms sales.

The Japanese government paper said the shifting balance between the US and China could unsettle the region.

''As China rapidly enhances its military power, changes in the military power balance between the United states and China may possibly affect the peace and stability of the Indo-Pacific region,'' the report said. ''It is necessary to pay greater attention to the military trends of the two countries in areas such as the South China Sea and Taiwan."

China labels report 'irresponsible' 

Japan also criticized Beijing for its ''relentless attempts to unilaterally change the status quo'' of disputed Japan-controlled East China Sea islands called Senkaku, calling it ''a violation of international law.''

China currently also claims almost all of the South China Sea and has built military bases on artificial islands in the disputed area.

Beijing responded to Japan's report, calling it "extremely erroneous and irresponsible." It also rebuked Japan's warning on Taiwan, saying that China only promoted peace in the region.

"Japan has for some time ... leveled unreasonable accusations against China's normal national defense construction and military activities, made irresponsible remarks about China's legitimate maritime activities, and exaggerated the so-called China threat," Foreign Ministry spokesperson Zhao Lijian said.

"We will never allow any country to interfere with the Taiwan issue in any way. China must and will surely be reunified, and it is in the best interest of regional peace and stability for China to achieve complete reunification," Zhao said at a daily briefing.

jcg/msh (AP, AFP)