The S&P skidded 2.7 percent, amid investor fears that tit-for-tat tariffs could raise prices, slow the economy and sow uncertainty among businesses.

The U.S. stiock market has dropped considerably over the last week amid concerns over the impacts of President Donald Trump's proposed tariffs.

U.S. stocks seesawed between positive and negative territory in early trading on Tuesday, remaining essentially unchanged after losses suffered Monday when markets reacted to President Donald Trump's refusal to rule out a possible recession.