After a highly unusual rally on the road to thank his supporters, President-elect Donald Trump was back in New York City on Friday to meet with potential cabinet appointees and advisers. But it was a phone call he had with the president of Taiwan that could have some serious consequences. Grace Rauh filed the following report.

After a campaign-like stop in Cincinnati, Donald Trump was back to the New York grind on Friday. But despite the ongoing intrigue over those passing through Trump Tower to meet with the president-elect, it was a phone conversation Trump had that stunned many and may lead to significant diplomatic fallout.

Trump's transition team confirmed that he spoke with the president of Taiwan, Tsai Ying-wen. The call is believed to be the first between an American president or president-elect in 37 years.

The U.S. and Taiwan do not have a diplomatic relationship, and any overture to Taiwan is expected to enrage China, which considers Taiwan part of its country.

At an event in Washington, before news of the call broke, former House Speaker Newt Gingrich said the president-elect needs to keep himself in check. Gingrich backed Trump during the campaign.

"The world is actually going to pay attention to what he says. So he cannot say things that haven't been thought through," Gingrich said.

Trump's pick for Defense Secretary, retired Marine Corps. General James Mattis, is also making waves. Mattis only retired from active military duty three years ago, far short of the seven-year break the law requires of anyone running the Pentagon. New York Sen. Kirsten Gillibrand, for one, says she intends to vote against the waiver he would need to get from Congress to accept the job.

Trump also announced a business advisory council packed with major CEOs. It will be led by Stephen Schwarzmann of Blackstone. Mary Barra of General Motors, Jamie Dimon from JPMorgan Chase and Doug Mcmillan from Wal-Mart are among the council's members.

As for Trump, he is expected to stay in the city this weekend. But next week, he will be back on the road for more thank-you rallies. He has an event on Tuesday in Fayetteville, North Carolina and another in Des Moines, Iowa on Thursday.