Donald Trump has introduced a fresh set of tariff rates on numerous countries, many of which now face significantly higher duties on their exports to the United States starting August 7. The move could pose a serious challenge to global economies,

Mr. Trump is also threatening tariff hikes for Mexico and China, but the U.S.' southern neighbor got a 90-day extension on Thursday, and an Aug. 12 deadline to strike a deal with China is expected to be extended for three months, too.