Japanese Prime Minister Yoshihide Suga referred to Taiwan as a country, immediately drawing fire on Thursday from mainland China, which regards the island as a renegade province.
In his first one-on-one parliamentary debate with opposition leaders Wednesday, Suga, naming Australia, New Zealand and Taiwan, said, "Such three countries have been imposing strong restrictions on privacy rights" to curb the novel coronavirus outbreak.
Self-governed Taiwan is usually called a "region" in Japan, with the Communist-led Chinese government claiming the island is an "inalienable part" of its territory.
Suga's reference came as Tokyo and Beijing have already been at odds over several issues, including a territorial dispute in the East China Sea and the crackdown on Hong Kong.
"China expresses strong dissatisfaction with Japan's erroneous remarks and has lodged a solemn protest against Japan," Foreign Ministry spokesman Wang Wenbin told reporters in Beijing on Thursday.
"There is only one China in the world," Wang said, urging Japan to become more cautious in words and deeds on Taiwan affairs and to avoid sending wrong signals to the island's independence forces.
Recently, Suga's government, which was launched in September 2020, has been strengthening its commitment to democratic Taiwan, irritating Chinese President Xi Jinping's leadership believed to be aiming to reunify the island with the mainland by force if necessary.
At his summit in Washington in April, Suga confirmed with U.S. President Joe Biden "the importance of peace and stability across the Taiwan Strait." It marked the first time in 52 years that Japanese and U.S. leaders have mentioned Taiwan in a joint statement.
Following the summit, the Chinese Foreign Ministry summoned a senior official of the Japanese Embassy in Beijing to lodge a protest against the agreement between the United States and its close security ally in Asia.
China has also lambasted Japan for having donated a COVID-19 vaccine to Taiwan, labeling such a move as a "political performance."
Taiwan and mainland China have been separately governed since they split in 1949 as a result of a civil war. Their relationship has deteriorated since independence-leaning Tsai Ing-wen became Taiwan president in 2016.
While Tokyo severed diplomatic ties with Taipei and established them with Beijing in 1972, Taiwan and Japan have continued to maintain relations primarily due to economic cooperation by the private sector.