American markets fell on Monday as the trade war between Washington and Beijing escalated. Both countries implemented tariffs on the other’s exports, and according to a report from CNBC, additional sanctions may still be levied on additional Chinese goods.

Worries were further compounded over the weekend when the Chinese government backed out of the upcoming trade talks with Washington. According to CNBC, Beijing has accused the United States of “trade bullyism,” and also accused the U.S. of trying to impose its agenda on other countries through economic means.

While China hurled accusations at the United States, Peter Navarro, director of the National Trade Council, fired back on Monday. The director told the hosts of CNBC’s “Closing Bell” that it’s “far more difficult to make a deal with China than it would be with Mexico.” Navarro cited China’s “egregious practices” in the past as the reason for the difficulty.

The S&P 500, Dow Jones Industrial Average, and the NASDAQ all closed lower on Monday afternoon. According to Reuters, the S&P 500 was down 0.26 percent at Monday’s close, while the Dow Jones Industrial Average lost 0.21 percent. The NASDAQ took the biggest hit and fell by 0.57 percent.