Coronavirus fears and the steep sell-off in crude oil caused U.S. markets to continue their precipitous fall, with the Dow Jones Industrial Average ending Monday's trading session down more than 2,000 points or 7.8%.

The S&P 500 fell 6.63% and the Nasdaq slipped 7.29% by the time trading closed.

Markets plunged early in the trading session, forcing a temporary halt to trading. The 15-minute halt was caused by an automatic circuit breaker safety mechanism that kicked in to prevent a free fall after the S&P 500 plunged by more than 7% within minutes of markets opening.

The recent decline in the markets has resurfaced concerns about a global economic slowdown.

"The only way to avoid a recession would be a quick and very aggressive fiscal policy response by the Trump administration," Moody’s Investor Services chief economist Mark Zandi told ABC News' Rebecca Jarvis. "But this seems unlikely as the administration continues to significantly downplay the severity of the crisis."

PHOTO: Trader Gregory Rowe prepares for the day's activity on the floor of the New York Stock Exchange, March 9, 2020. (Richard Drew/AP)

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Monday's market plunge came after OPEC talks fizzled over the weekend and Saudi Arabia slashed oil prices, triggering a price war and sending U.S. crude oil prices plunging by more than 25% -- fanning even more uncertainty among investors.

Moody's Investor Services also issued a revised economic outlook report Monday, warning that "global recession risks have risen" and "several unknowns make for a highly unpredictable environment."

"There are several unknowns, including the future spread of the virus and the economic consequences. The degree of uncertainty around our forecasts is unusually high, and far more severe scenarios are possible," according to Moody's. It added that many financial factors could "snowball into deeper economic contraction."

"The fact that all economies, big and small, are simultaneously facing this same negative shock would reinforce the recessionary cycle," analysts at Moody's wrote.

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Amid the market volatility and uncertainty, many analysts are urging investors to focus their attention long term.

"The guidance for long-term investors remains intact -- do not panic. As the uncertainty persists, the market frenzy will continue, perhaps for weeks, perhaps for months," Greg McBride, the chief financial analyst at Bankrate, said in a note. "But long-term investors must think in terms of years or decades.”

"The uncertain economic impact of coronavirus continues to grip markets, with stocks, commodities and interest rates all dropping sharply. Markets hate uncertainty and there is a ton of it currently in play," he added. "Markets fall sharply, but can also rebound quickly. No one knows when that comes and you don’t want to be sitting on the sidelines when that happens."

PHOTO: A person wears a face mask walks along Wall Street after further cases of coronavirus were confirmed in New York, March 6, 2020. (Andrew Kelly/Reuters, FILE)

Daniel Ives, the managing director of equity research at Wedbush Securities, reiterated that investors should "take a deep breath" and focus on their long-term goals.

"This morning with markets seeing an avalanche of selling pressuring triggering circuit breakers, we encourage investors to take a deep breath and focus on the tech winners for the next 5-10 years including Apple front and center," he said in a note, referencing news that iPhone sales in China plummeted last month. "While this is a very nervous time for consumers, companies, investors," he believes it is a "shock-event" and demand for iPhones in China will soon normalize.

The yield on the 10-year Treasury note dropped to an unprecedented low of 0.408%, a possible signal that investors are expecting a recession.

Among the worst performers Monday were Dow Inc (which fell more than 21%), Chevron Corp (which fell more than 15%) and Caterpillar Inc (which shed more than 14%). Meanwhile, demand for haven assets including gold spiked.

Dow sinks more than 2,000 points amid coronavirus uncertainty and plunging oil prices originally appeared on abcnews.go.com