U.S. President Donald Trump on Tuesday held out the possibility of an extension of the 90-day trade truce he and Chinese President Xi Jinping agreed on over the weekend that would freeze tariffs while a broader deal is negotiated.

"The negotiations with China have already started. Unless extended, they will end 90 days from the date of our wonderful and very warm dinner with President Xi in Argentina," Trump said on Twitter.

Trump and Xi on Saturday agreed to the cease-fire in a trade war that has seen the flow of hundreds of billions of dollars worth of goods between the world's two largest economies disrupted by tariffs.

The two leaders said they would hold off on imposing additional tariffs for 90 days starting Dec. 1 while they seek a solution to their trade disputes.

The United States expects China to take immediate action to cut tariffs on U.S. car imports and end intellectual property theft and forced technology transfers as the two countries move toward a broader trade deal, Larry Kudlow, director of the White House National Economic Council, said on Monday.

The appointment of U.S. Trade Representative Robert Lighthizer to lead the talks instead of Treasury Secretary Steven Mnuchin puts one of the administration's toughest China critics in charge. Trump said in the Twitter post that Lighthizer would work closely with Mnuchin, Kudlow and trade adviser Peter Navarro.