The number of people infected with coronavirus surpassed 100,000 across the world on Friday as the outbreak reached more countries and intensified economic damage, with business districts beginning to empty and stock markets tumbling.

An increasing number of people were asked to stay home from work, schools were closed, large gatherings and sports and music events were cancelled, stores were cleared of staples like toiletries and water, and face masks became a common sight. The outbreak has killed more than 3,400 people and spread across more than 90 nations, with six countries reporting their first cases on Friday.

The World Health Organization (WHO) said every country should make containing the epidemic its top priority, pointing to Iran's national action plan to combat one of the worst outbreaks after a slow start.

Iran's death toll from the virus jumped to 124, as more than 1,000 new cases were diagnosed over 24 hours. In the United States, the world's economic powerhouse, at least 57 new cases of coronavirus were confirmed as the virus struck for the first time in Colorado, Maryland, Tennessee and Texas, as well as San Francisco in California. Some 230 people have been infected in total and 12 have died.

More than 2,000 people were stranded on the Grand Princess cruise ship after it was barred from returning to port in San Francisco because at least 35 people aboard developed flu-like symptoms. Test kits were delivered at sea. U.S. President Donald Trump signed a bill allocating $8.3 billion to bolster testing for the virus and other action.

SUPPLY CHAINS BROKEN Moves by some major economies including the United States to cut interest rates and pledge billions of dollars to fight the epidemic have done little to allay fears about the spread of the disease and the economic fallout. Supply chains are crippled around the world, especially in China, where the outbreak began.

"There's concern that while there has been a response from the Fed, given the nature of the problem, is this something the central bank can really help with?" said John Davies, G10 rates strategist at Standard Chartered Bank in London.

In New York, JPMorgan divided its team between central locations and a secondary site in New Jersey while Goldman Sachs sent some traders to nearby secondary offices in Greenwich, Connecticut and Jersey City.

In London, Europe's financial capital, the Canary Wharf district was unusually quiet. S&P Global's large office stood empty after the company sent its 1,200 staff home, while HSBC asked around 100 people to work from home after a worker tested positive for the illness. Facebook said it was closing its London offices until Monday after a visiting employee from Singapore was diagnosed with the virus.

European stocks continued their slide after the Japanese market dropped to a six-month low, with 97% of shares on the Tokyo exchange's main board in the red.

Airline and travel stocks have been among the worst affected as people cancelled non-essential travel. Norwegian Air Shuttle , the hardest-hit stock among European carriers, lost more than quarter of its market value on Friday and has fallen almost 70% since the start of February.

"If this really ramps up, we could see a lot more kitchen-sinking updates from the travel industry and airlines," said Chris Beauchamp, chief market analyst at IG.

MARKETS HIT Yields on U.S. Treasuries plunged to historic lows on Friday as fears the outbreak will slam the global economy drove investors to snap up risk-adverse assets and dump equities, overshadowing data highlighting a strong U.S. labour market.

MSCI's gauge of stocks across the globe shed 1.87% and emerging market stocks lost 2.43%. In Europe, the pan-regional STOXX 600 index fell 3.35%. The travel and leisure sub-index slid 3.9%. New York's Dow Jones Industrial Average fell 1.5%.

More than 100,300 people have been infected globally, according to a Reuters tally based on statements from health ministries and government officials. Mainland China has seen more than 3,000 deaths, but the epidemic is now spreading faster elsewhere. The death toll in Italy, which has suffered Europe's worst outbreak, rose to 197. About 3.4% of confirmed cases of the new coronavirus - known as COVID-19 - have died, far above seasonal flu's fatality rate of under 1%, the WHO said this week.

Singapore reported 13 new infections on Friday, its biggest daily jump, including a Singapore Airlines cabin crew member. Google, Facebook, Amazon, and Microsoft advised employees in the Seattle area to work from home, after some caught the virus. The companies' work-from-home recommendation will affect more than 100,000 people in the area.