By Fred Imbert and Eustance Huang, CNBC–

Stocks fell once again Friday, capping their worst week since the financial crisis as worries over the coronavirus and its impact on the economy continued to rattle investor sentiment.

The Dow Jones Industrial Average closed down 357 points, or 1.4%. The 30-stock Dow briefly fell more than 1,000 points. The S&P 500 slid 0.8%, while the Nasdaq Composite closed flat. The major indexes cut their losses in the final minutes of trading.

For the week, the Dow fell more than 12%, its biggest weekly percentage loss since 2008. On a points basis, the Dow fell more than 3,500 points. It also ended the week in correction territory, down 14.1% from a record high set Feb. 12. The S&P 500 lost 11.5% week to date in its worst weekly performance since the crisis.

A pledge by the Federal Reserve late Friday eased the market’s pain slightly into the close.. Fed Chairman Jerome Powell said in a statement the central bank will “act as appropriate” to support the economy amid the coronavirus outbreak.

“What we have right now is a very scary global health scare, that has caused complex supply chains to stall,” said Art Hogan, a market strategist at National Securities. “As such we have a supply shock currently. Easier monetary policy could help if we were to evolve into a demand shock with the economic damage the follows the path of COVID-19. Rate cuts are not only the wrong prescription for what ails the economy right now, they are bad medicine longer term since they could raise prices without a supply response.”

The major averages were under pressure Friday in part because investors kept adding to their bond market exposure and fleeing equities. The benchmark U.S. 10-year Treasury yield touched a fresh record low. It was last at 1.14%. Yields move inversely to prices.

Among the latest coronavirus headlines the market was responding to, a Google employee tested positive for the coronavirus, the company said Friday. New Zealand and Nigeria reported overnight their first coronavirus cases. South Korea, meanwhile, confirmed more than 500 new cases. China reported 327 additional cases.

Caterpillar, a bellwether stock for global growth, slid 2.3%. Apple shares dropped 2.9% and entered bear market territory. Boeing and JPMorgan Chase fell more than 5% each. Google-parent Alphabet dropped 2%.

The Cboe Volatility Index hit 47.15, its highest level since February 2018. It last traded around 41.

The Dow plummeted nearly 1,200 points Thursday — its biggest one-day point drop ever — as worries over the coronavirus possibly spreading sent stocks spiraling lower. The 30-stock average closed in correction territory along with the S&P 500 and Nasdaq Composite.

“The reason it happened so quickly is because the momentum going up was so great,” said Liz Ann Sonders, an investment strategist at Charles Schwab. “The hedge funds, the algorithmic trading, the quants: They play on momentum.”

The Dow had closed at a record high on Feb. 12. It took the S&P 500 only six days to fall from an all-time high into correction levels, marking the broad index’s fastest drop of that magnitude outside of a one-day crash.

“People have been so preconditioned to buy the dip and to always expect the market to recover that people can get smacked around with moves like this,” said Patrick Hennessy, a trader at IPS Strategic Capital. “No one knows how this thing ends.”

Friday’s losses built on this week’s massive losses. The Dow and S&P 500 have fallen 14% and 13%, respectively, week to date. The two indexes were on pace for their biggest one-week loss since the 2008 financial crisis. The Nasdaq has lost 12.3% this week.

Travel stocks Norwegian Cruise Line and American Airlines are among the worst-performing S&P 500 stocks this week, dropping more than 20% in that time. Las Vegas Sands has lost more than 10% week to date. Regeneron Pharmaceuticals is the only S&P 500 component that is higher for the week.

“The timing of this was just the worst with respect to investor sentiment being elevated,” said Doug Ramsey, an investment officer at The Leuthold Group, referring to the coronavirus outbreak. “I’m not sure that the market has really priced in the potential economic impact of this.”

Concerns over the coronavirus have also led several companies to issue earnings and revenue warnings. Microsoft said Wednesday one of its key divisions may not meet the company’s previous revenue guidance. PayPal also warned about its outlook on Thursday.

Goldman Sachs’ David Kostin warned U.S. companies will see no earnings growth this year. “Our reduced profit forecasts reflect the severe decline in Chinese economic activity in 1Q, lower end-demand for US exporters, disruption to the supply chain for many US firms, a slowdown in US economic activity, and elevated business uncertainty,” said Kostin, the bank’s chief U.S. equity strategist.

The outbreak has also raised questions over potential intervention from central banks around the world. Kevin Warsh, a former Federal Reserve governor, told CNBC’s “Squawk Box” he expects global monetary policy makers to take action soon in response to the virus spreading. However, St. Louis Fed President James Bullard said rate cuts are only a possibility if the coronavirus turns into a pandemic.