He later said China had committed to buying large amounts of United States agricultural products and completely removing all tariffs on U.S. automobiles, a huge shift from its current 40 per cent penalty.
White House officials have already begun backpedaling on President Trump's claim of an agreement with China to drop tariffs on United States cars entering the world's largest automotive market. Targeting soybeans was widely seen as a direct attack on Trump's supporters, as the US' top soybean farming states voted for Trump in 2016.
The accumulating list of irritants and flashpoints between the USA and its trading partners could spill over through other, less obvious channels such as confidence, financial markets and investment, compounding other threats such as rising US interest rates and capital flight from emerging markets...
Markets, however, pulled back sharply after Monday's rally as doubts crept in over what could realistically get accomplished in the tight negotiating window.
The Dow Jones industrial average sank almost 600 points, or 2 percent, to 25,245.
The announcement came as part of a 90-day halt in which the president will delay a scheduled tariff increase on China, Fox News noted.
But, he added, "I'm sure secretary Mnuchin will be deeply involved as well". "The market is trying to figure out: "Is there going to be a real deal at the end of 90 days or not?'" Mnuchin told the Wall Street Journal CEO Council". Still, "the market is very concerned about the outcome of further negotiations", and whether there will be big purchases in the next few weeks, she said.
At the G20 Summit in Argentina last weekend, . the two leaders agreed to a temporary truce, . with President Trump agreeing to maintain 10-percent tariffs on 200-billion dollars worth of Chinese goods, and not raise them to 25-percent.
Trump tweeted: "China has agreed to reduce and remove tariffs on cars coming into China from the U.S. now the tariff is 40%".More news: Urban Meyer "Retires" At Ohio State
A lack of detail from the Chinese side has left investors and analysts wondering if Trump's exuberance is premature, and if details touted by the White House but left out of Chinese reporting on the agreement are in question.
The US expects China to take immediate action to cut tariffs on US vehicle imports and end intellectual property theft and forced technology transfers as the two countries move toward a broader trade deal, Kudlow, director of the White House National Economic Council, said Monday.
The changes USA officials have sought include forcing Beijing to lower tariffs on USA goods, stop dumping cheap steel and aluminium into foreign markets, and halting the theft of intellectual property, among other things.
The U.S. LNG sector also needs Chinese participation, however.
The U.S. embassy in Beijing posted a Chinese version of the White House's readout of the meeting on the popular WeChat platform on social media, but reposting it was not possible.
Mr Trump has long accused China of unfair trade practices that hurt USA citizens and the economy.
The White House said Beijing had promised to buy an unspecified but "very substantial" amount of agricultural, energy, industrial and other products, with purchases of farm goods to start "immediately".
His appointment of Lighthizer to lead the talks instead of Mnuchin puts one of the administration's toughest China critics in charge.
White House trade director Peter Navarro detailed on Monday what the administration hopes to accomplish by lifting tariffs on China for 90 days.