Stocks across the globe fell after a historic three-day run-up, with indexes poised to close the month and quarter with starkly negative performances.
The volatility of the erratic markets is expected to continue as the coronavirus pandemic that triggered closures in economies worldwide remains very much a threat.
The United States surpassed two grim milestones as virus-related deaths soared past 1,000 and it become the world leader in confirmed cases.
The uncertainty over the overall human and economic toll was reflected in financial markets, with MSCI's gauge of global stocks on track to post both its largest weekly percentage gain since 2008 and its largest monthly and quarterly drops since 2008.
The infection rate for the coronavirus is driving much of the market at a time of great uncertainty, said Yousef Abbasi, global market strategist at INTL FC Stone Financial Inc in New York.
Stock markets have rallied over the past week on trillions of dollars of enacted and pledged economic stimulus by policymakers worldwide, from central banks to governments.
Policymakers may need to offer more stimulus as the virus slams the brakes on economic activity and increases healthcare spending.
"Next week, markets will likely continue to focus on the spread of COVID-19 - whether European cases are reaching a peak, how much of the .. will be put in lockdown, and whether China can avoid a second wave," said Gaétan Peroux, strategist at UBS Global Wealth Management.
The US House of Representatives is expected to pass a $2.2 trillion stimulus package that will flood the world's largest economy with money to stem the economic damage caused by the pandemic.
Amid the avalanche of stimulus, the US dollar was little changed for the day and remained on track for its biggest weekly decline since May 2009.
The US currency's fall after two weeks of steep gains suggests the Federal Reserve's efforts to relieve a crunch in the dollar funding market are working, some analysts said.
Three day rally in Europe comes to an end
European shares slumped today after a three-day rally sparked by hopes of more aggressive stimulus to shore up the global economy ravaged by the rapid spread of the coronavirus pandemic.
Shares in London had tanked 5.9% this afternoon after British Prime Minister said he had tested positive for the coronavirus.
Shares in Paris had slumped 4.6% while the Frankfurt market was down 3.5%.
Dublin shares were also lower this afternoon, declining by 4.5% with Flutter Entertainment and Dalata Hotel Group seeing more heavy falls.
More than $3 trillion has been wiped from the value of European firms since the outbreak of Covid-19.
With the pandemic still far from contained in Europe, the bloc has suspended state aid rules and limits on public borrowing and approved $40 billion worth of emergency funds to help airlines, among the hardest hit sectors in the global emergency.
Earlier in Asian trade, Tokyo's Nikkei jumped 3.9% while the Hang Seng index in Hong Kong gained 0.56% to as investors welcomed a blockbuster US stimulus plan.
No way to get to strong recovery without containment
The head of the International Monetary Fund on Friday underscored the importance of strong containment measures to get control of the coronavirus pandemic, and to lay the groundwork for a strong recovery in 2021.
IMF Managing Director Kristalina Georgieva told CNBC that the global community was coming together to respond to the crisis with strong fiscal measures, and the response had been greater than during the 2008-2009 global financial crisis.
But she warned against stepping away from containment efforts too soon, adding, "There is no way to come to a strong recovery without strong containment."