President Donald Trump demanded U.S. companies stop doing business with China and announced he would raise the rate of tariffs on Beijing Friday, capping one of the most extraordinary days in the long-running U.S.-China trade war.

By the end of the trading day, the Dow Jones industrial average had fallen 600 points, or nearly 2.4 percent; the business community had ratcheted up criticisms of the president; and world leaders descending on the Group of Seven summit in France were confronted with the prospect of a global slowdown, triggered by a trade war with no end in sight.

The dizzying series of events Friday pushed the trade war between the world’s economic superpowers into a dangerous new phase. Several developed nations appear to be slipping into recession, and many governments and companies had hoped that recent signs of economic weakness in China and the United States would push the parties to the bargaining table.