Chinese Foreign Minister Wang Yi called Taiwan's newly-inaugurated President Lai Ching-te "disgraceful" on Tuesday, stepping up Beijing's rhetoric just a day after he took office.
China, which claims Taiwan as its own territory, believes Lai to be a "separatist", and has rebuffed his offers of talks.
China's government has generally avoided directly naming Lai since he won election in January, unlike in the run-up to the vote where they regularly denounced him by name and said the election was a choice between war and peace.
Speaking at a foreign ministers meeting of the Shanghai Cooperation Organisation in Kazakhstan, Wang said Taiwan was the "core of core issues" for China, and independence activities the most destructive factor for peace in the Taiwan Strait.
"The ugly acts of Lai Ching-te and others who betray the nation and their ancestors is disgraceful," China's foreign ministry cited Wang as saying.
Nothing can stop China from achieving "reunification" and bringing Taiwan "back to the motherland", he added.
"All Taiwan independence separatists will be nailed to the pillar of shame in history."
Taiwan's foreign ministry said China's coercive practices would not sway the island.
"Political coercion and diplomatic suppression by the authoritarian Chinese government will never change Taiwan's staunch democratic convictions," it said.
Lai, like his predecessor Tsai Ing-wen, says only Taiwan's people can decide their future, rejecting Beijing's sovereignty claims.
China on Tuesday also admonished the United States for sending its congratulations to Lai, after scolding South Korean and Japanese lawmakers for visiting Taiwan despite its strong opposition.
Lai received loud applause after reiterating that the Republic of China - Taiwan's formal name - and the People's Republic of China are "not subordinate to each other", a line Tsai also took.
China views such wording as tantamount to saying China and Taiwan are different countries, a red line for Beijing.
China says any move by Taiwan to declare formal independence would be grounds to attack the island.
The government in Taipei says Taiwan is already an independent country, the Republic of China. The Republican government fled to Taiwan in 1949 after losing a civil war with Mao Zedong's communists who set up the People's Republic of China.
