The Foreign Ministry in Beijing has slammed US Secretary of State Mike Pompeo over a congratulatory message he sent to Taiwan President Tsai Ing-wen, saying it has "severely damaged peace, China-US ties and cross-strait relations".
It also warned that China will take necessary countermeasures and that the "US must bear the consequences".
Pompeo sent a message to Tsai who started her second term on Wednesday, hailing her "courage and vision in leading Taiwan's vibrant democracy" – a rare direct message from a US administration official.
Beijing said the US action violates the promise it made and sent a wrong signal to “Taiwan independence separatist forces".
Earlier the Taiwan Affairs Office in Beijing also issued a statement, saying Beijing will "never tolerate" Taiwan's separation, but that it would adhere to the principles of "peaceful reunification" and "One Country, Two Systems".
The statement came after Tsai during her inauguration for a second term again rejected Beijing's offer and said both sides need to find a way to coexist peacefully.
Ma Xiaoguang, spokesman for the Taiwan Affairs Office, said China had "sufficient ability to defend national sovereignty and territorial integrity", according to official state news agency Xinhua.
Beijing would "never tolerate any separatist activities or external forces interfering in China's internal politics", he said.
Ma said China said was willing to "create a vast space for peaceful reunification", but will "not leave any room for all forms of Taiwanese independence separatist activities".
Tsai is loathed by Beijing because she views Taiwan as a de facto sovereign state and not part of "one China". (Reuters, AFP)