Declines were led by the technology sector for a second straight session. Tech-related heavyweights Microsoft Corp, Amazon.com Inc and Apple Inc were the biggest drags on the S&P 500.
The S&P technology index dropped 2.3%. Chipmakers, which have strong ties to China, also fell sharply. The Philadelphia Semiconductor index ended down 3%.
China reported a jump in new cases on Friday, while South Korea became the latest hot spot, with 100 new cases, and more than 80 people tested positive for the virus in Japan.
"It's creating a wild card" for companies and investors, said Peter Tuz, president of Chase Investment Counsel in Charlottesville, Virginia. "Going into a weekend not so long after the stock market was hitting highs, people are taking some money off the table."
Apple earlier this week issued a sales warning, citing the impact of the virus outbreak.
The worries pushed up Wall Street's fear gauge, the CBOE volatility index, and caused investors to seek safe-haven assets. The VIX hit its highest closing level since Feb. 3.
Gold and bond prices rose and some defensive equity sectors, including staples, ended the day higher.
The IHS Markit Purchasing Managers' index of services sector activity dropped to its lowest level since October 2013, signaling a contraction for the first time since 2016. The manufacturing sector also clocked its lowest reading since August.
The Dow Jones Industrial Average fell 227.57 points, or 0.78%, to 28,992.41, the S&P 500 lost 35.48 points, or 1.05%, to 3,337.75 and the Nasdaq Composite dropped 174.38 points, or 1.79%, to 9,576.59.
For the week, the Dow was down 1.4% and the S&P 500 lost 1.3%. The Nasdaq shed 1.6%, its biggest weekly percentage decline in three weeks.
Hopes of monetary easing by major central banks had propelled the S&P 500 and the Nasdaq to all-time highs earlier this week.
Also on Friday, Dropbox Inc jumped 20% after it raised its outlook for operating margin, and Deere & Co rose 7% after an unexpected rise in first-quarter profit.
Sprint Corp climbed 6% as it announced new merger terms with T-Mobile US showing a reduction in the stake of major Sprint shareholder SoftBank. T-Mobile shares dipped 0.9%.
Declining issues outnumbered advancing ones on the NYSE by a 2.17-to-1 ratio; on Nasdaq, a 2.25-to-1 ratio favored decliners.
The S&P 500 posted 30 new 52-week highs and 8 new lows; the Nasdaq Composite recorded 74 new highs and 59 new lows.
Volume on U.S. exchanges was 8.28 billion shares, compared with the 7.66 billion average for the full session over the last 20 trading days.
(Additional reporting by Sruthi Shankar and Manas Mishra in Bengaluru; Editing by Anil D'Silva, Chizu Nomiyama and Dan Grebler)
By Caroline Valetkevitch
