Investors are winding down another volatile week with U.S. stocks are pace to wrap a losing week. Federal Reserve Chairman Jerome Powell fired a warning over tariffs, on Thursday President Trump clapped back calling for Powell to cut rates.

Investors who may have been hoping the Federal Reserve is poised to come to the aid of tariff-rattled markets took away an unwelcome message from the central bank's chief on Wednesday: the Fed may be in a bind.

Wall Street tumbled after Fed Chair Jerome Powell warned about the impact of tariffs and Nvidia issued sobering guidance.