The US trade agreement with Vietnam reportedly lowers tariffs but lacks detail, triggering sharp warnings from Chinese officials.

Against a ticking clock, President Donald Trump said Wednesday the United States has reached a trade agreement with Vietnam, pulling off the administration’s third significant deal ahead of a self-imposed July 9 deadline.

SINGAPORE—A tariff agreement with Vietnam emphasizes one of the White House’s top priorities in this frantic round of dealmaking over global trade: Slamming shut any back door routes for Chinese goods to enter the U.