With details scant and officials in both countries mum on the issue of American-made autos, industry experts were left guessing as to what the president meant.
BEIJING — After the negotiations over steak dinners were done, after he said his goodbyes to President Xi Jinping of China and after both governments issued their public statements about the trade truce between the United States and China, President Trump had one more surprise to drop.
In a late-night Twitter post on Sunday, Mr. Trump said that China had agreed to make a small but politically significant concession to the United States: It would drop tariffs on imports of American-made cars.
“China has agreed to reduce and remove tariffs on cars coming into China from the U. S.,” he wrote. “Currently the tariff is 40%.”
The disclosure took trade watchers and auto industry figures in both countries by surprise. The issue of auto tariffs had not appeared in the public disclosures from either the United States or Chinese governments issued after the two sides hammered out their temporary trade-war truce.
It was unclear what China had agreed to do, if it had agreed to do anything at all. A spokesman for the Chinese Foreign Ministry referred questions to the Commerce Ministry. That ministry was silent, and its weekly news conference is not until Thursday. American officials were unavailable for comment.
The confusion is perhaps inevitable. Chinese leaders hoard information as a way of bolstering their political power. Add to that Mr. Trump’s predilection for trying to summarize complex issues in Twitter posts of a few words, and the potential for confusion can grow quickly.
