US will honour 'One China' policy, Trump promises Xi

US President Donald Trump has promised to honour the "one China" policy in an effort to ease diplomatic tensions between the two countries, the White House said in a statement.

The two leaders spoke on the phone on Thursday night, the statement said, their first conversation since Trump's inauguration on January 20.

"They discussed numerous topics and President Trump agreed, at the request of President Xi, to honour the 'One China' policy," the White House said.

The policy dictates that Washington recognises Beijing as the only official government of China and will not establish formal relations with, Taiwan, The Hill magazine reported.

The White House described the Trump-Xi call as "lengthy" and "extremely cordial", and said both men had extended invites to each other visit their respective countries.

Trump angered the Chinese government by accepting a call from Taiwanese President Tsai Ing-wen after his election, breaking with a long-standing protocol.

An American president or president-elect had not spoken with Taiwan's leader since 1979.

China considers Taiwan to be a breakaway region, one that will re-unite with the mainland some time in the future.

The current US policy of not recognising Taiwan was put in place under President Jimmy Carter in order to establish formal ties with China.

Responding to Trump's remark, President Xi said he appreciated Trump's adherence to the policy.

"China will work with the United States to enhance communication and cooperation so that bilateral ties can advance in a sound and stable manner and yield more fruits to benefit the two peoples, and people of all countries in the world," the Global Times reported Xi as saying.

The two leaders last spoke on November 14, days after Trump was elected President.

In recent days, there were signs the White House was trying to smoothen the tensions with China, the magazine said.

Trump sent a belated letter to Xi on Wednesday wishing him a happy Lunar New Year. His daughter Ivanka and her husband Jared Kushner, who is a senior adviser to the President, last week attended the Chinese embassy's New Year's reception in Washington.

The call came one day before Trump is set to meet with Japanese Prime Minister Shinzo Abe in Washington, after which they will fly on Air Force One to Trump's Palm Beach club, where they will play golf.