BEIJING — President Donald Trump reaffirmed America’s long-standing “one China” policy in a call with Chinese President Xi Jinping, dealing a victory to Beijing on an issue it considers nonnegotiable and possibly helping to ease uncertainty between the nations.

Trump’s latest remarks, coming after he repeatedly suggested using the policy as leverage, appeared aimed at reassuring Beijing he would not seek to upend relations between the world’s two-largest economies.

“This is an important step,” said Bonnie Glaser, senior adviser on Asia at the Center for Strategic and International Studies in Washington, D.C. “This will now pave the way for the engagement of the U.S. and Chinese governments on a wide range of issues.”

The policy in place since 1979 requires Washington to maintain only unofficial ties with Taiwan, the self-governing island that China claims as its own territory. China views any hint of official U.S. recognition of the island as anathema to China’s revival as a great Asian power.

The long-awaited call between Xi and Trump came Thursday evening, Washington time, the White House and China’s state broadcaster CCTV said.

The two leaders discussed “numerous” topics at length and Trump agreed to honor the “one China” policy, the White House said — though it said Trump did so “at the request of President Xi.” It described the call as “extremely cordial” and said the two leaders had invited each other to visit their respective countries and looked forward to further discussions.

Xi “praised” Trump’s affirmation of relations, CCTV reported, and said China was willing to work with the U.S. to bring “more fruitful gains for the benefit of our two peoples and those in every country.”