WASHINGTON (AP) — The escalation of the U.S.-China trade fight comes at a particularly inopportune moment for the global economy, when growth in the United States and the world is already weakening.

The trade tensions threaten to turn a period of slower growth into recession. The conflict could also spread to currency markets and threaten to involve other countries.

In the past week, President Donald Trump has said he will impose new taxes on hundreds of billions of dollars of Chinese imports. Beijing responded by halting purchases of U.S. farm goods and allowing the value of its currency to fall to an 11-year low.

Sung Won Sohn is an economist at Loyola Marymount University in California. She says the rapid-fire sequence of events “shatters confidence, trust and expectations.”