The United States and China have sharply raised tariffs on each other’s imports over the last week, raising the prospect of a long and painful trade war between the world’s two largest economies.

Even as investors rallied to his decision to pause “reciprocal” tariffs on imports from dozens of countries Wednesday, President Donald Trump raised tariffs on Chinese goods to 125 percent — an increase of more than 20 percent and his fourth tariff action against Beijing since January. President Xi Jinping has not backed down, either, retaliating by raising China’s tariffs on U.S.-made goods to 84 percent and imposing new curbs on critical resources.

The intensifying financial hostilities represent a potentially significant threat to the United States and global economies regardless of the delay in higher tariffs for other trading partners. Government officials in Beijing and Washington have, for years, girded for a major clash between the two superpowers, and some economists say further escalation could do perhaps as much to push the U.S. into a recession as Trump’s initial tariff proposal would have.