China's foreign minister said Saturday he hopes Beijing's relations with the U.S. would not be "interfered with or damaged" after President-elect Donald Trump broke with decadeslong diplomatic tradition and spoke directly with Taiwan's leader.
It is highly unusual, probably unprecedented, for a U.S. president or president-elect to speak directly with a leader of Taiwan, a self-governing island the U.S. broke diplomatic ties with in 1979.
Chinese Foreign Minister Wang Yi said the call between Taiwan's president and Trump 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.
Washington has pursued a so-called "one China" policy since 1979, when it shifted diplomatic recognition of China from the government in Taiwan to the communist government on the mainland. Under that policy, the U.S. recognizes Beijing as representing China but retains unofficial ties with Taiwan.
A statement from Trump's transition team said he spoke with Ing-wen, who offered her congratulations.
"During the discussion, they noted the close economic, political, and security ties ... between Taiwan and the United States. President-elect Trump also congratulated President Tsai on becoming President of Taiwan earlier this year," the statement said.
Trump tweeted later: "The President of Taiwan CALLED ME today to wish me congratulations on winning the Presidency. Thank you!"
About an hour later, Trump groused about the reaction to the call. "Interesting how the U.S. sells Taiwan billions of dollars of military equipment but I should not accept a congratulatory call," he tweeted.
The Taiwanese presidential office issued a statement early Saturday saying Trump and Tsai discussed issues affecting Asia and the future of U.S. 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.
"The president also told U.S. President-elect Trump that she hopes the U.S. will continue to support Taiwan's efforts in having more opportunities to participate in and contribute to international affairs in the future," Tsai's office said.
It said the two also "shared ideas and concepts" on "promoting domestic economic development and strengthening national defense" to improve the lives of ordinary people.
The White House learned of the conversation after it had taken place, said a senior Obama administration official, who requested anonymity because of the sensitive diplomatic relations involved.
DNC spokesman Eric Walker called Trump's Taiwan call "foolish" and accused the president-elect of prioritizing his personal fortune over the U.S.'s security interests.
"Donald Trump is either too incompetent to understand that his foolish call threatens out national security, or he's doing it deliberately because he reportedly wants to build hotels in Taiwan to pad his own pockets," Walker wrote.
Friday's call is 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 lent by the State Department, which oversees U.S. diplomacy.
Tsai was democratically elected in January and took office in May. The traditional independence-leaning policies of her party have strained relations with Beijing.
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 amid civil war in 1949. The U.S. policy acknowledges the Chinese view over sovereignty, but considers Taiwan's status as unsettled.
Although the U.S. does not have formal diplomatic ties with Taiwan, it has close unofficial ties. Taiwan's government has a representative office in Washington and other U.S. cities. The U.S. also has legal commitments to help Taiwan maintain the ability to defend itself.
Taiwan is separated from China by the 110-mile-wide Taiwan Strait. The island counts the U.S. as its most important security partner and source of arms, but it is increasingly outgunned by China.
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.
"We remain firmly committed to our 'one China' policy," Price said. "Our fundamental interest is in peaceful and stable cross-strait relations."
The NSC stressed that every president has benefited from the "expertise and counsel" of the State Department on matters like this, which suggested that the White House was frustrated by Trump's conversation with the Taiwanese leader.
Still, the White House said Obama remains committed to a smooth transition to the new administration.
Diplomatic protocol dictates that Taiwanese presidents can transit through the U.S. but not visit Washington.
Douglas Paal, who served as head of the American Institute in Taiwan during the George W. Bush administration, said that to his knowledge the call was unprecedented. He said he expected Beijing to issue a verbal warning that there's no space to change the rules over Taiwan relations.