The U.S. government said Wednesday that it will impose 25% tariffs on automobile imports on April 3 and a similar duty on auto parts a month later, as President Donald Trump prepared to announce further trade barriers that could escalate a trade war and upend the global economy.

After months of delays, President Donald Trump's contentious tariff barrage is now in effect. It imposes a wide variety of new import taxes that are the steepest seen in nearly a century and affect all of the country's trade partners.