US President-elect Donald Trump has spoken with Taiwanese President Tsai Ing-wen, in a major break with Washington's policy on China, triggering protest from Beijing.
During Friday's discussion, Trump and Tsai noted "the close economic, political and security ties" between Taiwan and the United States, according to the president-elect's transition team.
"President-elect Trump also congratulated President Tsai on becoming president of Taiwan earlier this year," it said.
The Hong Kong-based South China Morning Post, quoting a Taiwanese presidential spokesman, reported that Tsai initiated the 10-minute call.
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China's foreign ministry said on Saturday that it had lodged a protest with the "relevant side" in the US after the call - the first such contact with Taiwan by a US president-elect or president since President Jimmy Carter adopted a "one China" policy in 1979.
As part of its so-called "one China" policy Washington shifted diplomatic recognition of China from the government in Taiwan to the communist government on the mainland.
The "one China" principle is the political basis of the China-US relationship, the Chinese foreign ministry added, urging the "relevant side" to uphold this policy and carefully handle the Taiwan issue to avoid unnecessary disturbances in ties.
Under that policy, the US recognises Beijing as representing China, but retains unofficial ties with Taiwan. Washington is Taiwan's most important political ally and sole arms supplier, despite the lack of formal diplomatic ties.
Al Jazeera's Adrian Brown, reporting from Beijing, said that the response from the Chinese government was swift. "A spokesperson said China opposes any official contact or military interactions between the US and Taiwan.
"It is not what was said that will upset China, but the symbolism of the US president-elect directly speaking to the Taiwanese leader," he said.
Defending the move
As he came under fire for the move, Trump defended the contact on Twitter.
He first tweeted that Tsai initiated the call, one of several he has had with world leaders in recent days, and brushed off criticism for speaking directly with the leader.
"Interesting how the US sells Taiwan billions of dollars of military equipment, but I should not accept a congratulatory call," Trump wrote in a second tweet sent an hour after the first one.
Alex Huang, a spokesman for Tsai, said: "Of course both sides agreed ahead of time before making contact."
China's Foreign Minister Wang Yi Wang said that the so-called "one China policy" is the cornerstone of US-China relations and that Beijing hoped that foundation would not be "interfered with or damaged" by Trump's move.
He blamed Taiwan for the exchange.
"This is just the Taiwan side engaging in a petty action, and cannot change the one China structure already formed by the international community," Wang said at an academic forum, Hong Kong-based Phoenix TV reported.
China views Taiwan as a renegade province.
During the election campaign, Trump referred to China as a currency manipulator and accused Beijing of raping the US economy.
The White House responded to the call by saying that "long-standing policy" on China and Taiwan has not changed.
"We remain firmly committed to our 'one China' policy," said Ned Price, a national security spokesman for President Barack Obama. "Our fundamental interest is in peaceful and stable cross-Strait relations."
The call comes at a time of worsened Taiwan-China relations since the election of Tsai's pro-independence Democratic Progressive Party (DPP) earlier this year.
Friday's call is the starkest example yet of how Trump has flouted diplomatic conventions since he won the November 8 election. He has apparently undertaken calls with foreign leaders without guidance customarily provided by the state department, which oversees US diplomacy.
Trump and Chinese President Xi Jinping spoke by telephone on November 14. Xi stressed that cooperation was the only choice for relations between the world's two largest economies, and Trump said that the two had established a "clear sense of mutual respect".
Source: Al Jazeera News and Agencies