China officials complained to the United States after President-elect Donald Trump flouted almost four decades of diplomatic protocol by directly speaking with the leader of Taiwan, which Beijing considers a rogue province.

The "solemn representation" on Saturday urged U.S. authorities to adhere to the so-called one-China principle and "prudently" handle issues related to the self-governed island.

Chinese Foreign Minister Wang Yi said that Trump's Friday telephone call with Taiwanese President Tsai Ing-wen was a "little trick pulled off by Taiwan," adding, "We don't want to see this political foundation disturbed and damaged."

The measured response suggested China's desire to keep the incident from escalating into a full-blown crisis before Trump entered the White House or even appointed a full foreign-policy team.

Statements from Trump's transition team and his subsequent comments on Twitter left unclear whether the call presaged a shift in long-standing U.S. policy against recognizing Taiwan's sovereignty or allowing direct communication between top leaders.

"This could be potentially explosive, but now is not the right time for Beijing to make the formal call on Trump's Taiwan policy because he's yet to take office," said Wang Fan, director of China Foreign Affairs University's Institute of International Relations. "He's still learning and doing his homework. China's measured response would give him some time to do a crash course on the history of Sino-U.S. relations."

Trump's transition team said in a statement that Taiwan's president congratulated the Republican on his victory and the two "noted the close economic, political and security ties" between the two sides. The call lasted more than 10 minutes, Taiwan's presidential office said in an e-mailed statement.

"The President of Taiwan CALLED ME today to wish me congratulations on winning the Presidency. Thank you!" Trump said later Friday on Twitter.

Later he added: "Interesting how the U.S. sells Taiwan billions of dollars of military equipment but I should not accept a congratulatory call."

The call was planned in advance with knowledge of Trump's transition team and was the right thing to do, said Stephen Yates, a former national security official who served President George W. Bush.

Yates denied multiple reports that he arranged the call, while adding that it doesn't make sense for the U.S. to be "stuck" in a pattern of acquiescing to China.

"If people are going to have these sort of hyperbolic - and in my view 'Chicken Little' reactions - to a phone call, imagine what it's going to be like when we have real substantive differences," Yates said in a telephone interview Saturday.

Engaging directly with Taiwan might lead instead to "some sense of rebalancing" of U.S. relations with Taiwan and China, Yates said. "The Chinese have imposed thought control, verbal control, behavior control on the United States," he said.

While ties between Beijing and Taipei have improved over the decades, China continues to have some 1,200 missiles aimed across the Taiwan Strait and has asserted its right to invade as a way to prevent any formal split. Tensions have increased since Tsai's landslide election win in January. Her party officially supports independence and she has personally refused calls to reaffirm the one-China principle.

Taiwanese presidential office spokesman Alex Huang said after the call that good Taiwanese-U.S. relations were as important as cross-strait ties. "It's in line with national interests, and critical to regional peace," Huang said. "Those are goals of the government and there's no conflict among the goals."

An Obama administration official, who spoke on condition of anonymity, said the White House wasn't notified about the call in advance. National Security Council spokesman Ned Price said, "There is no change to our longstanding policy on cross-Strait issues," adding that the U.S. remained "firmly committed to our 'one China' policy."

Before Trump's call Friday, Chinese President Xi Jinping was meeting in Beijing with former Secretary of State Henry Kissinger, 93, a key architect of restored ties between the two sides during the Nixon years, to discuss the U.S. situation. Xi told Trump in a telephone call Nov. 14 that cooperation was the only correct choice for relations between the two powers.

Trump's phone call may also raise fresh conflict-of-interest questions about the president-elect. A Taiwanese newspaper reported on Nov. 16 that Trump was considering building luxury hotels and resorts in Taoyuan City, a major industrial center with an airport that serves Taipei, citing the city's mayor.

Trump's organization denied reports of planned expansion in Taiwan, ABC News reported Saturday on Twitter.