Shares in automakers around the world tumbled on Thursday after President Trump announced plans to impose a 25 percent tariff on imported cars and some parts beginning next week.

Among the hardest hit were carmakers based in Germany, Japan and South Korea, which sell many of their cars in the United States and rely on complex supply chains that cross borders, including from production sites in Mexico and Canada.

Shares in Germany’s Volkswagen, Europe’s largest automaker, fell 1.5 percent. Other German carmakers like Mercedes-Benz and BMW dropped 2 to 3 percent in early European trading.

Stellantis, the parent of Chrysler, Fiat, Jeep, Peugeot and Ram, saw its European shares fall about 4 percent.

The stocks of Japan’s Toyota Motor, Honda Motor and Nissan Motor all fell about 2 percent in Tokyo. Shares in South Korea’s Hyundai Motor and Kia fell 3 to 5 percent in Seoul.

The major Detroit carmakers, which build some of their vehicles in Canada and Mexico, were also hit hard. Shares in General Motors were down more than 6 percent in premarket trading and Ford’s shares were about 3 percent lower.

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