NEW YORK (AP) — Donald Trump has spoken with the president of Taiwan, a self-governing island the U.S. broke diplomatic ties with in 1979.

It is highly unusual, perhaps unprecedented, for a U.S. president or president-elect to speak directly with a Taiwanese leader. The U.S. cut formal diplomatic ties with Taiwan when it shifted diplomatic recognition of China to the communist government on the mainland, although Washington still has close unofficial ties with Taipei.

Trump’s transition team says the two leaders noted the “close economic, political, and security ties” that exist between Taiwan and the United States.