NEW YORK -- U.S. president-elect Donald Trump is using Twitter to renew his defence of his engagement with the leader of Taiwan, a breach of diplomatic protocol as the U.S. shifted recognition from Taiwan to China nearly 40 years ago.

In a series of Sunday evening tweets, Trump groused about criticism that he didn't work with China ahead of the contact. China considers Taiwan a rogue province.

"Did China ask us if it was OK to carry out a number of actions such as build up disputed islands in the South China Sea or take economic measures hurtful to the United States," Trump tweeted.

The Taiwanese leader, Tsai Ing-Wen, called Trump Friday to congratulate him on the election in communication arranged by an American third party. Taiwan's official Central News Agency, citing anonymous sources on Saturday, said that Edwin Feulner, founder of the Washington-based Heritage Foundation, was a "crucial figure" in setting up communication channels between the sides.

The call prompted an understated complaint from China to the U.S. government. Foreign Minister Wang Yi said Saturday that the contact was "just a small trick by Taiwan" that he believed would not change U.S. policy toward China, according to Hong Kong's Phoenix TV.

"The one-China policy is the cornerstone of the healthy development of China-U.S. relations and we hope this political foundation will not be interfered with or damaged," Wang was quoted as saying. Chinese officials said they lodged a complaint with the U.S. and reiterated a commitment to seeking "reunification" with the island, which they consider a renegade province.

The call was the starkest example yet of how Trump has flouted diplomatic conventions since he won the Nov. 8 election. He has apparently undertaken calls with foreign leaders without guidance customarily given by the State Department, which oversees U.S. diplomacy.

"President-elect Trump is just shooting from the hip, trying to take phone calls of congratulatory messages from leaders around the world without consideration for the implications," said Bonnie Glaser, senior adviser for Asia at the Center for Strategic and International Studies in Washington.

Vice-President-elect Mike Pence said Sunday that the phone call shouldn't necessarily be interpreted as a shift in U.S. policy. He shrugged off the attention to the incident as media hype.

"It was a courtesy call," Pence told NBC's "Meet the Press."

But other Trump supporters suggested the move was calculated.

"I think it was a terrific message to them that we're no longer going to be pushovers, and there's going to be consequences for their hostile and aggressive actions," California Republican Rep. Dana Rohrabacher, who says he is under consideration to become the next secretary of state, told Fox News on Monday.

Over the decades, the status of Taiwan has been one of the most sensitive issues in U.S.-China relations. China regards Taiwan as part of its territory to be retaken by force, if necessary, if it seeks independence. It would regard any recognition of a Taiwanese leader as a head of state as unacceptable.

Taiwan split from the Chinese mainland in 1949. The U.S. policy acknowledges the Chinese view over sovereignty, but considers Taiwan's status as unsettled.

Ned Price, a spokesman for the White House National Security Council, said Trump's conversation does not signal any change to long-standing U.S. policy on cross-strait issues. Yet the phone conversation prompted mixed reactions.

Douglas Paal, a former director of the American Institute in Taiwan, which unofficially represents U.S. interests in Taipei, said it was too soon to judge whether Trump was going to lead that shift, or if the incident was just a "complicated accident."

"Beijing will watch closely to see which it is," said Paal, now vice-president for studies at the Carnegie Endowment for International Peace.

The U.S. shifted diplomatic recognition to China from Taiwan in 1979. But the governments in Washington and Taipei have maintained close unofficial ties and deep economic and defence relations. The U.S. is required by law to provide Taiwan with weapons to maintain its defence, and since 2009, the Obama administration has approved $14 billion in arms sales to Taiwan.

The Taiwanese presidential office said Trump and Tsai discussed issues affecting Asia and the future of U.S. relations with Taiwan. Tsai also told Trump that she hoped the U.S. would support Taiwan in its participation in international affairs, the office said, in an apparent reference to China's efforts to isolate Taiwan from global institutions such as the United Nations.

Taiwan's presidential office spokesman, Alex Huang, said separately that Taiwan's relations with China and "healthy" Taiwan-U.S. relations can proceed in parallel. "There is no conflict" in that, he said.

China's foreign ministry said Beijing lodged "solemn representations" with the U.S. over the call.

"It must be pointed out that there is only one China in the world and Taiwan is an inseparable part of Chinese territory," Geng Shuang, a ministry spokesman, said in a statement. "The government of the People's Republic of China is the sole legitimate government representing China."

Associated Press writers Matthew Pennington and Darlene Superville in Washington, Johnson Lai in Taipei, and Nomaan Merchant and news researcher Henry Hou in Beijing contributed to this report