America's relationship with China could potentially be in jeopardy after President-elect Donald Trump spoke with Taiwan President Tsai Ing-wen by phone Friday. It marked the first time a U.S. president or incoming president has spoken with the leader of the island nation since the 1970s, when formal diplomatic ties between the countries were severed.

The Financial Times initially reported about the phone call between the two leaders.

The U.S. cut formal diplomatic ties with Taiwan when it shifted diplomatic recognition of China to the communist government on the mainland, but the two countries have maintained unofficial diplomatic relations since 1979 — the same year the U.S. embassy in Taiwan closed.

"President-elect Trump spoke with President Tsai Ing-wen of Taiwan, who offered her congratulations," according to a readout of the call from Trump's transition team obtained by Newsmax.

"During the discussion, they noted the close economic, political, and security ties exists between Taiwan and the United States. President-elect Trump also congratulated President Tsai on becoming President of Taiwan earlier this year."

The President of Taiwan CALLED ME today to wish me congratulations on winning the Presidency. Thank you! — Donald J. Trump (@realDonaldTrump) December 3, 2016



Evan Medeiros, the former Asia director at the White House national security council, told the Times Friday's phone call could be seen as "highly provocative" in China's view.

"The Chinese leadership will see this as a highly provocative action, of historic proportions," Medeiros said.

"Regardless if it was deliberate or accidental, this phone call will fundamentally change China's perceptions of Trump's strategic intentions for the negative. With this kind of move, Trump is setting a foundation of enduring mistrust and strategic competition for U.S.-China relations."

Trump spoke with other world leaders on Friday as well, including Philippines President Rodrigo Roa Duterte and Singapore Prime Minister Lee Hsien Loong.

The Trump transition team had this to say about the call with Duterte: "In their conversation, they noted the long history of friendship and cooperation between the two nations, and agreed that the two governments would continue to work together closely on matters of shared interest and concern."

Regarding the phone call between Trump and Loong, the transition team said: "The two men discussed the long history of good economic, political, and security relations between the United States and Singapore."

The New York Times reports that the White House was not aware of the call until after it occurred.

Trump has had conversations with more than 50 world leaders, according to The Wall Street Journal. One of those leaders was Chinese President Xi Jinping.

Five days after Trump won the presidency, the Journal reported that he spoke on the phone with Xi. The pair, according to Trump's office, had a candid conversation.

"During the call, the leaders established a clear sense of mutual respect for one another, and President-elect Trump stated that he believes the two leaders will have one of the strongest relationships for both countries moving forward," Trump's office told the Journal at the time.

Sen. Chris Murphy, a Connecticut Democrat, is a member of the Senate Foreign Relations Committee and posted a series of tweets Friday regarding Trump's foreign policy:

(1) Foreign policy consistency is a means, not an end. It's not sacred. Thus, it's Trump's right to shift policy, alliances, strategy. — Chris Murphy (@ChrisMurphyCT) December 2, 2016



(2) What has happened in the last 48 hours is not a shift. These are major pivots in foreign policy w/out any plan. That's how wars start. — Chris Murphy (@ChrisMurphyCT) December 2, 2016



(3) And if they aren't pivots - just radical temporary deviations - allies will walk if they have no clue what we stand for. Just as bad. — Chris Murphy (@ChrisMurphyCT) December 2, 2016



(4) It's probably time we get a Secretary of State nominee on board. Preferably w experience. Like, really really soon. — Chris Murphy (@ChrisMurphyCT) December 2, 2016



Sen. Brian Schatz, a Democrat from Hawaii, also took to Twitter asking for clarity on the phone call.

1 - The world needs clarity on this Taiwan phone call. 2 - We really need a steady hand at State Department. Tomorrow would be perfect. — Brian Schatz (@brianschatz) December 2, 2016

Information from the Associated Press was used in this report.