UNITED NATIONS – US Ambassador Nikki Haley met Wednesday with the acting President of the Taiwan Affairs Office, three days after US Secretary of State Mike Pompeo left the island in an effort to tackle Taiwan’s claim of leadership in the island.

The National Security Council declined to say who attended the meeting with Matthew Tung.

The US has maintained the formal independence of its diplomatic relationship with Taiwan since 1979 and international firms are prohibited from doing business in the Chinese-ruled island. Beijing also said a former Taiwanese President, Chen Shui-bian, had been unable to return to Taiwan despite attempts to persuade him to sign up as a candidate at last week’s election.

But the Australian-educated Tung said in July that while he opposed any formal change of Washington’s policies toward Taiwan, he “would welcome US advocacy for freedom of political expression and peaceful protest” for Taiwan. In a previous move that drew anger from Beijing, a senior US official in 2016 urged US companies to consider moving more operations offshore to Taiwan to avoid damaging relations with China.

The Washington Post said Tuesday’s meetings were discussed with Taiwan’s President Tsai Ing-wen and the Trump administration. On Tuesday, the National Security Council referred reporters to the White House about the meeting without elaborating.

It follows China’s diplomatic campaign to secure the re-election of Tsai, even though she cannot legally become Taiwan’s president because she is a Taiwanese.

At her presidential inauguration, Tsai said she was willing to enter into formal peace talks with China if Beijing agreed to abandon its current policy of “one China” and accept Taiwan as part of China.

China considers Taiwan, ruled by Tsai’s Nationalist regime, to be a renegade province to be taken back by force if necessary.

Tsai’s election came after her predecessor, Tsai Ing-wen, agreed to expand the scope of her administration’s talks with the United States, including possibly lifting a veto against a US law that bars trade with China.

But Beijing swiftly accused Tsai of secretly abandoning her previous promise, warning that “international legitimacy” for Washington’s dealings with Taiwan would be jeopardised.