Stocks slumped on Friday as shares of Amazon led the major indexes lower on the month’s first day of trading.

Concerns over a potential trade skirmish between China and the U.S. also dented sentiment.

The Dow Jones Industrial Average fell 600 points, or 2.5%, as Dow Inc and Exxon Mobil each fell more than 6%. The S&P 500 dropped 2.8% with consumer staples and communications stocks leading the broad market index down. The Nasdaq Composite traded 3% lower as a host of big-tech names fell.