China has lodged a diplomatic protest following Trump's call with Taiwan's president
The call on Friday was the first time a US president had spoken directly with Taiwan's leadership in more than 30 years and could strain US-China relations. The US broke formal ties with Taiwan in 1979, taking on a One-China position - switching diplomatic recognition from Taiwan to China - as it looked to establish diplomatic channels with Beijing.
China's Foreign Ministry has now moved to lodge "stern representations" with "the relevant US side," according to the Reuters report.
"The one China principle is the political basis of the China-US relationship," the China Foreign Ministry added.
Chinese state news agency Xinhua said the Ministry had urged the US "to cautiously, properly handle Taiwan issue to avoid unnecessary disturbance to Sino-US relations," according to the BBC.
Earlier on Saturday, China's foreign minister Wang Yi dismissed the phone call as "just a small trick by Taiwan" that he hoped would not affect the US' China policy, 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.
Trump's transition team said on Friday the Taiwanese president had called him to offer her congratulations on his election victory.
The statement said: "During the discussion, they noted the close economic, political, and security ties" between Taiwan and the United States. The statement continued. "President-elect Trump also congratulated President Tsai on becoming President of Taiwan earlier this year."
Trump tweeted later on Friday, saying: "The President of Taiwan CALLED ME today to wish me congratulations on winning the Presidency."
The President-elect followed that tweet up with another, in a response to critics: "Interesting how the US sells Taiwan billions of dollars of military equipment, but I should not accept a congratulatory call."
Prominent geopolitical expert Ian Bremmer slammed Trump's decision to take the phone call from President Tsai Ing-wen. He tweeted that Beijing will be "absolutely incensed" and told Business Insider: "Trump is just taking all sorts of calls of congratulations and has ignored both protocol and intel briefings. This is his first serious misstep accordingly. We'll surely see more."
However, Trump adviser and former campaign manager Kellyanne Conway brushed off concerns about the unprecedented conversation with Taiwan's president.
In an interview with CNN's Anderson Cooper, Conway accused Democrats of blowing things out of proportion. She pointed specifically to a tweet from Democratic Sen. Chris Murphy of Connecticut saying Trump's approach to foreign policy is "how wars start."
"This is how wars start and it's a major policy shift because he had a phone call? That's pretty negative and pretty presumptuous," Conway said. "This is the president elect, this will be his administration, he'll be commander-in-chief, and he'll be president of the United States imminently ... he's well aware of what US policy has been."