President-elect Donald Trump is unapologetic about roiling diplomatic waters with his decision to speak on the phone with Taiwan‘s leader, a breach of long-standing tradition that risks enmity from China.

The US severed diplomatic ties with the self-governing island in 1979, but has maintained close unofficial relations and a commitment to support its defense.

Trump’s conversation with Taiwanese President Tsai Ing-wen drew an irritated, although understated, response from China, as Foreign Minister Wang Yi said Saturday that the contact was ``just a small trick by Taiwan‘’ that he believed would not change US policy toward China, according to Hong Kong‘s Phoenix TV.

``The One-China policy is the cornerstone of the healthy development of China-US 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 US and reiterated a commitment to seeking ``reunification’‘ with the island, which they consider a renegade province.

After the phone conversation Friday, Trump tweeted that Tsai ``CALLED ME.’‘ He also groused about the reaction to the call: ``Interesting how the US sells Taiwan billions of dollars of military equipment but I should not accept a congratulatory call.’‘

The US 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 defense relations. The US is required by law to provide Taiwan with weapons to maintain its defense.

Since 2009, the Obama administration has approved $14 billion in arms sales to Taiwan.

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 US 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.

Over the decades, the status of Taiwan has been one of the most sensitive issues in US-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 US 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 US policy on cross-strait issues.

The Taiwanese presidential office said Trump and Tsai discussed issues affecting Asia and the future of US relations with Taiwan. ``The (Taiwanese) president is looking forward to strengthening bilateral interactions and contacts as well as setting up closer cooperative relations,’‘ the statement said.

Tsai also told Trump that she hoped the US 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-US relations can proceed in parallel. ``There is no conflict‘’ in that, he said.

China‘s foreign ministry said Beijing lodged ``solemn representations’‘ with the US 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.‘’

China is likely to be trying to identify whether this signals any intent on the part of Trump to alter long-standing US policy toward Taiwan, Glaser said.

``They will hope that this is a misstep, but I think privately, they will definitely seek to educate this incoming president and ensure that he understands the sensitivity of Taiwan,‘’ she said.

Last month, Trump had a call with Chinese President Xi Jinping during which Trump‘s office described him as saying he believed the two would have ``one of the strongest relationships for both countries.’‘

Despite China’s muted response Saturday, concern about Trump‘s policy toward China is growing, said Shi Yinhong of Renmin University in Beijing, one of China’s best-known international relations scholars.

Tsai was elected in January and took office in May. The traditional independence-leaning policies of her party have strained relations with Beijing.

The call with Trump could ``convince people in Taiwan that the island can establish good relations with the US and encourage to continue to resist pressure from Beijing,‘’ Shi said.

In Beijing, a US business group urged the new US administration to respect the status quo.