WASHINGTON — President Donald Trump overruled advisers to ramp up tariffs on China after a heated exchange in which he insisted levies were the best way to make Beijing comply with U.S. demands, according to people familiar with the matter.

Barring a break in the impasse, the U.S. is now poised to impose 10% tariffs on roughly $300 billion in Chinese imports that aren’t currently taxed starting Sept. 1. Battle lines are hardening in Beijing as well — raising prospects that a deal may be put off until after the U.S. presidential election next year.