US President-elect Donald Trump has spoken directly with the president of Taiwan – breaking with US policy set in 1979 when formal relations were cut.
Mr Trump’s transition team said the two leaders noted “close economic, political, and security ties” between the US and Taiwan in a phone call.
China sees Taiwan as a breakaway province, and has threatened to take the island by force if necessary.
Beijing has so far made no public comment on the latest development.
Mr Trump’s team also said that the president-elect “congratulated” Tsai Ing-wen on becoming the president of Taiwan in January’s elections.
Ms Tsai, Taiwan’s first female leader, led the Democratic Progressive Party (DPP) to a landslide victory in the poll.
The DPP has traditionally leaned towards independence from China.