At midday, the Dow Jones Industrial Average plunged 254.26 points, or 1.05 per cent, to 23,908.89. The S&P 500 decreased 13.92 points, or 0.53 per cent, to 2,634.13, Xinhua news agency reported.
The Nasdaq Composite Index was down 8.22 points, or 0.12 per cent, to 7,058.05.
Investors will also keep a close eye on Apple's earnings report, which will be released on Tuesday after the closing bell.
On the economic front, the seasonally adjusted IHS Markit final US Manufacturing Purchasing Managers' Index (PMI) registered 56.5 in April, up from 55.6 in March and indicated the strongest manufacturing growth in over three-and-a-half years.
Investors also looked to the Federal Reserve as the central bank began a two-day monetary policy meeting. Market participants are not expecting any interest rates hikes but they will be on the lookout for clues about the central bank's views on inflation and the economy.
(This story has not been edited by Social News XYZ staff and is auto-generated from a syndicated feed.)
