Stocks are sharply swinging down, up, then down again on Wall Street as markets try to assess the potential damage from President Donald Trump’s global trade war.

The Dow Jones Industrial Average briefly erased a morning loss of 1,700 points, shot up more than 800 points, then went back to a loss of 414 points.

The S&P 500 likewise made sudden up-and-down lurching movements and was down 1.3% in the first hour of trading.

The Nasdaq composite was down 0.8% That followed sharp drops around the world as worries rise about whether Trump’s trade war will torpedo the global economy.