Japan's deputy defence minister has warned of a growing threat posed by Chinese and Russian collaboration and said the world must "wake up" to Beijing's pressure on Taiwan and protect the island "as a democratic country".
Speaking to the Hudson Institute think tank, State Minister of Defence Yasuhide Nakayama questioned whether the decision of many countries, including Japan and United States, to follow a "one-China" policy that has recognised Beijing over Taipei since the 1970s would stand the test of time.
"Was it right?", he asked at the online event, referring to how future generations will judge politicians on the issue, "I don't know".
Nakayama said democratic countries had to protect each other and noted he had in the past referred to Taiwan as a "red line".
"So we have to protect Taiwan as a democratic country," he said.
Nakayama said Japan and Taiwan were geographically close, and added if something happened in Taiwan it would affect Japan's Okinawa prefecture, where US forces and their families are based.
The minister highlighted growing threats posed by China in space, in missile technology, in the cyber domain and in nuclear and conventional forces, and said that under President Xi Jinping's leadership the nation had "aggressive, aggressive ... thought and will".
"So wake up. We have to wake up," he said.
China claims democratically governed Taiwan as an integral part of its territory.
"We deplore the erroneous remarks by the senior official of the Japanese government, and we have lodged solemn representations," Chinese foreign ministry spokesman Wang Wenbin said, adding Nakayama had "falsely accused" China over "normal national defence developments".
"This is highly sinister, dangerous and irresponsible," Wang said.
"This politician also openly called Taiwan a country, in serious violation of the China-Japan joint statement."
Nakayama said it was necessary to show deterrence to China and also to Russia, which had stepped up exercises in Japanese-claimed territory and near the US territory of Hawaii.
"You can see China and Russia collaborating together, when they are doing some military exercise around our neighbours," Nakayama said, adding he wanted to see the United States "stronger, stronger and stronger".