Wall Street stocks finished another rocky session much lower Monday amid partisan squabbling over a giant stimulus package as the Federal Reserve announced new emergency measures.
The Dow Jones Industrial Average sank 3.0 percent, or nearly 600 points, to 18,591.93.
The broad-based S&P 500 sank 2.9 percent to 2,237.40, while the tech-rich Nasdaq Composite Index dipped 0.3 percent to 6,860.67.
Stocks sold off aggressively after the Senate again failed to advance a trillion-dollar rescue package as major cities in the United States ordered most businesses shut to try to limit the spread of the coronavirus.
Earlier, the Fed had announced several new initiatives to prop up the economy.
The central bank announced it will buy unlimited amounts of US Treasury debt -- essentially printing money for the economy -- as well as new steps to lend directly to small- and medium-sized companies that have been among the hardest-hit as economic activity dries up.
The Fed said it also plans to soon announce a "Main Street Business Lending Program," and pledged it "will continue to use its full range of tools to support the flow of credit to households and businesses."
Analysts welcomed the steps, but many expect markets to remain brittle until the world's biggest economy gets a grip on the virus outbreak.
The United States now has 41,000 declared cases, with more than 12,000 confirmed cases in New York City, the financial capital.
"We're going to need to see these growth rates restabilize in order for markets to heal," said Matt Jozoff, managing director, fixed income research.
Dow member Boeing enjoyed a rare positive session, surging 11.2 percent following an upgrade from Goldman Sachs, which predicted the aerospace giant would survive the dual hits of the 737 MAX grounding and a brutal crisis in the airline sector due to the virus.
Shares of the company were also boosted by an announcement that it would suspend production at an Everett, Washington manufacturing center but not lay off staff.
The announcement implies the company will secure federal backing after it pressed for $60 billion in support for the US aerospace industry.