President Donald Trump left his top advisers scrambling on Monday to explain a trade deal he claimed he'd struck with China to reduce tariffs on U.S. cars exported to the country — an agreement that doesn't exist on paper and hasn't been confirmed in Beijing. In the day after Trump announced the deal in a two-sentence Twitter post, the White House provided no additional information. At a briefing in Beijing, a spokesman for the foreign ministry declined to comment on any changes to car tariffs.