Wall Street stocks tumbled early Monday amid lingering uncertainty over Donald Trump’s trade policy as the president slammed Federal Reserve Chair Jerome in a new social media post.

Stocks had opened lower after China warned other countries against negotiating trade deals with the United States at Beijing’s expense.

But equities fell further shortly after the market opened when Trump called Powell a “major loser” for not cutting interest rates, underscoring questions about whether Trump will attempt to fire Powell in a move that would further unnerve markets.

About 40 minutes into trading, the Dow Jones Industrial Average was down 1.7 percent at 38,469.41.

The broad-based S&P 500 declined 1.9 percent to 5,180.16, while the tech-rich Nasdaq Composite Index shed 2.5 percent to 15,878.28.

Trump’s attack on Powell “creates more uncertainty,” said Adam Sarhan of 50 Park Investments.

“Nobody knows what’s going to happen going forward,” Sarhan said. “And the fear that, we might actually have a recession unfold is stronger than anything else right now.”

Among individual companies, Netflix climbed 1.5 percent following better than expected results as revenues rose following subscription price hikes.

This week’s earnings calendar includes reports from Tesla, Boeing and Procter & Gamble.

Also on the agenda will be the annual spring meetings in Washington at the International Monetary Fund and World Bank.