President Donald Trump's punishing tariffs rocked global financial markets on Thursday, with the dollar and U.S. stocks tumbling as investors rushed to safe havens on fears a broadening trade war would push an already fragile world economy into recession.

Mr. Trump insists that these actions are his way of standing up for farmers and ranchers. Other nations such as Japan, China and India have charged higher tariffs than the U.S. for importing American farm goods.