Chris Murphy at a press conference in Washington in 2015 AP Photo/Andrew Harnik Sen. Chris Murphy of Connecticut blasted Donald Trump in a Friday evening tweetstorm after the president-elect made a phone call to the president of Taiwan.

The move that could strain US relations with China. Trump's call to President Tsai Ing-wen is the first time a US president has directly spoken with Taiwan's leadership in more than 30 years.

The US suspended formal diplomatic relations with Taiwan in 1979 after establishing a One China position in an effort to establish diplomatic channels with Beijing.

In a tweetstorm, Murphy warned that Trump's "major pivots in foreign policy" are "how wars start":

Trump has not yet announced his pick for secretary of state, but former Massachusetts Gov. Mitt Romney, former New York City Mayor Rudy Giuliani, and retired Gen. David Petraeus are all said to be in the running.

At least one sitting US senator backed Trump's phone call on Friday. Republican Sen. Tom Cotton posted a statement on his website saying: "I commend President-elect Trump for his conversation with President Tsai Ing-wen, which reaffirms our commitment to the only democracy on Chinese soil."