Stocks struggled worldwide on Friday with most indices ending sharply lower amid mounting worries the coronavirus outbreak will dent global economic growth.

The Dow slid more than two percent losing more than 600 points in its worst session since August as the three largest US carriers halted all service to China.

Just after markets closed, US authorities declared a public health emergency, and starting Sunday will ban entry into the country of any foreign national who has traveled to China in the past two weeks, while quarantining Americans who have made the trip.

Major European markets slid more than one percent, including London, where equities were weakened by a stronger pound in the final session before Britain was due to leave the European Union.

Asian equity markets also were gripped by virus fears in a volatile end to the week, although Japan's Nikkei finished higher.

At least 213 people have died and nearly 10,000 people have been infected in China by the novel coronavirus, while fresh cases were found abroad with more than 20 countries now affected.

"Unless a cure is found, this could push a fragile world economic recovery into reverse," warned Douglas McWilliams, deputy chairman at British research group the Centre for Economics and Business Research (CEBR).

Oxford Economics analysts said the outbreak would have a large short-term impact on Chinese economic growth and possibly curb global GDP growth by 0.2 percentage points this year.

"It's increasingly apparent the disease is becoming an economic as well as a public health concern," they said.

The WHO invoked a global health emergency on coronavirus -- but stopped short of recommending trade and travel restrictions that could have had a bruising effect on China, a key global growth engine.

After initially applauding the WHO action, investor fear returned as Britain confirmed its first cases and Italy declared a state of emergency to fast-track efforts to prevent its spread after two cases were confirmed in Rome.

Quincy Krosby, chief market strategist at Prudential Financial, said the outbreak has raised doubts about whether growth would accelerate in the aftermath of the US-China trade detente.

"We expected to see global growth," she said. "What this does is perhaps slows that down and adds more uncertainties."

Krosby said the outbreak also could pose problems for companies with supply chain dependent on China.

Separately, the EU's official statistics agency announced Friday that the 19-member single currency area already suffered a sharp slowdown after a turbulent year of Brexit uncertainty and trade spats with US President Donald Trump.

The eurozone economy grew 1.2 percent over the year, down from 1.8 percent in 2018 and well off the 2.7 percent seen in 2017.

Losses were broad-based on Wall Street, but an exception was Amazon, which surged 7.4 percent after releasing quarterly earnings results for the holiday period that trounced market expectations.

Markets rose after the WHO said there was no need for some of the stringent international travel and trade restrictions imposed in a bid to halt the spread of the deadly new virus Markets rose after the WHO said there was no need for some of the stringent international travel and trade restrictions imposed in a bid to halt the spread of the deadly new virus Photo: AFP / Sergei SUPINSKY

New York - DOW: DOWN 2.1 percent at 28,256.03 (close)

New York - S&P 500: DOWN 1.8 percent at 3,225.52 (close)

New York - Nasdaq: DOWN 1.6 percent at 9,150.94 (close)

London - FTSE 100: DOWN 1.3 percent at 7,286.01 (close)

Frankfurt - DAX 30: DOWN 1.3 percent at 12,981.97 (close)

Paris - CAC 40: DOWN 1.1 percent at 5,806.34 (close)

EURO STOXX 50: DOWN 1.4 percent at 3,640.91 (close)

Hong Kong - Hang Seng: DOWN 0.5 percent at 26,312.63 (close)

Tokyo - Nikkei 225: UP 1.0 percent at 23,205.18 (close)

Shanghai - Composite: Closed for a public holiday

Pound/dollar: UP at $1.3205 from $1.3093 at 2200 GMT

Euro/pound: DOWN at 84.00 from 84.26 pence

Euro/dollar: UP at $1.1094 from $1.1032

Dollar/yen: DOWN at 108.33 from 108.96

Brent Crude: DOWN 0.2 percent at $58.16 per barrel

West Texas Intermediate: DOWN 1.1 percent at $51.56 per barrel