U.S. stock index futures slipped lower Tuesday after President Donald Trump’s abrupt removal of Federal Reserve Governor Lisa Cook sparked heightened concerns over the central bank’s independence.

At 05:55 ET (09:55 GMT), Dow Jones Futures fell 70 points, or 0.2%, S&P 500 Futures dropped 6 points, or 0.1%, and Nasdaq 100 Futures slipped 19 points, or 0.1%.

The major indices closed lower Monday, as the new week started with a losing session in the wake of Friday’s big rally. The blue chip Dow Jones Industrial Average dropped 0.8%, the broad-based S&P 500 fell 0.4% and the tech-heavy NASDAQ Composite slipped 0.2%.