"The US economy is navigating through a soft patch and high valuations are elevating the risk of being wrong so investor angst and concern remains high," Terry Sandven, who helps oversee US$126 billion as chief equity strategist at US Bank Wealth Management in Minneapolis, told Bloomberg.
In late trading in New York, the Dow Jones Industrial Average slid 0.89 per cent, the Standard & Poor's 500 Index dropped 1.14 per cent, while the Nasdaq Composite Index declined 1.51 per cent.
Slides in shares of Intel and those of DuPont, last down 2.5 per cent and 2.2 per cent respectively, led the drop in the Dow.
It wasn't all bad news however. The Institute for Supply Management's non-manufacturing index rose to 57.8 last month, the highest since November, from 56.5 in March.
Shares of Microsoft fell, last 0.8 per cent weaker, after Bloomberg reported the company was considering a bid for salesforce.com, citing people familiar with the matter.
In Europe, the Stoxx 600 Index ended the session with a 1.5 per cent drop from the previous close. It gave up earlier gains of as much as 1.1 per cent. The UK's FTSE 100 Index slid 0.8 per cent, France's CAC 40 Index retreated 2.1 per cent, while Germany's DAX dropped 2.5 per cent.
In Greece, the ASE Index slumped 3.9 per cent amid concern the country won't be able to fulfill the requirements to unlock another chunk of international financial aid before a May 12 deadline.
Oil climbed, rising to the highest level in 2015, as protesters in Libya disrupted crude flows. US crude settled at US$60.40 a barrel, after earlier in the day rising as high as US$61.10.
To be sure, some said the gains in crude might prove shortlived.
"I think the market is getting ahead of itself," Dominick Chirichella, senior partner at the Energy Management Institute in New York, told Reuters.
"There's plenty of producer hedging going on as well, and those production levels are not going to come down if demand projections are not met. This could simply mean we are setting ourselves up for another leg lower in prices."