U.S. stock indexes got rocked on Monday, with the major benchmarks ringing up losses of at least 7% and marking their worst daily declines in years, as the eruption of an oil-price war between OPEC and Russia and rising coronavirus fears sparked heavy losses across global equity markets.

Steep losses in early trade triggered a rarely used circuit breaker that temporarily halted trading across stock markets.

The Dow Jones Industrial Average DJIA, -0.87% closed down 2,013.76 points, or 7.8%, at 23,851.02, while the S&P 500 SPX, -1.11% fell 225.81 points, or 7.6%, to end at 2,746.56, near its session low. The Nasdaq Composite Index COMP, -1.07% plunged 624.94 points, or 7.3%, to finish at 7,950.68. All three benchmarks suffered their biggest one-day percentage declines since 2008.

Market Extra:How an ‘oil shock’ and coronavirus combined to wreak havoc on stocks and global financial markets

What’s driving the market?

U.S. stocks markets closed near bear-market territory, defined as fall of 20% from a recent peak, on Monday, fittingly on the 11th anniversary of the bull market that began March 9, 2009.

See:Stocks will enter a bear market if the Dow and S&P 500 close below these levels

A combination of growing concerns about the COVID-19 outbreak, amplified by a powerful selloff in crude-oil prices and energy-related companies amplified the markets lurch lower.

“The slide in the oil price, along with further outbreaks of coronavirus across Europe, and the Italian government imposing a lock down across northern Italy and in around the Milan region, has accelerated the rush for the exits in stock markets sending U.S. bond yields to new record lows,” said Michael Hewson, chief market analyst at CMC Markets UK, in a note.

West Texas Intermediate crude for April delivery US:CLJ20 ended down 25% at $31.13 a barrel, while May Brent crude UK:BRNK20, the global benchmark, tumbled 24% to $34.36 a barrel. Both grades notched their sharpest one-day declines since the 1991 Gulf War.

The slump for crude came after a 10% drop on Friday after talks between the Organization of the Petroleum Exporting Countries and their allies collapsed, with Russia refusing to agree to a Saudi-led plan for additional crude production cuts. In response, Saudi Arabia over the weekend slashed crude prices and is preparing to increase production, in a direct attack against Russia’s market share, The Wall Street Journal reported.

See:An all-out war for dominance has erupted among OPEC and its allies, and now oil investors brace for a race to the bottom on prices

Goldman Sachs analysts on Sunday said a price war could push crude prices toward $20 a barrel, especially as the economic slowdown caused by the coronavirus outbreak slows global demand. Those price levels “will start creating acute financial stress and declining production from shale as well as other high-cost producers,” Goldman warned.

Read:Goldman says coronavirus and oil ‘price war’ could see crude plunge into the $20s

Meanwhile, on the COVID-19 front, Italy virtually locked down its northern region, containing about a quarter of its population, on Sunday in an effort to slow the spread of the coronavirus outbreak. Meanwhile, a number of schools closed in California and events were canceled, as a cruise ship hit by coronavirus prepared to dock in Oakland on Monday, with authorities preparing plans to transport the 3,500 passengers to military bases around the country for testing and quarantine. As of Sunday, the virus had sickened 107,897 people world-wide, with 3,658 deaths.

Economists at Oxford Economics wrote that with “COVID-19 cases rising in multiple hot spots outside China and markets in retreat,” the research firm sees “a major risk of sustained and significant disruption being exacerbated by tighter credit conditions.”

“A global recession may not yet be an inevitable consequence of the coronavirus outbreak, but even a modest surge in bad news could make it our baseline view,” the economists said in a Monday report.

There are now 111,284 cases of COVID-19 and 3,892 deaths, according to the latest figures compiled by Johns Hopkins University. More than 62,000 people have recovered. However, the outbreak in Italy (7,375 cases and 366 deaths) has now surpassed Iran (7,161 cases and 237 deaths) and is nearly as large as the outbreak in South Korea (7,478 cases and 53 deaths) in terms of case count.

Erik Knutzen, chief investment officer at Neuberger Berman, said he doesn’t believe stocks have put in a bottom.

“It will be weeks, at the earliest, before we have a clear idea of the global economic impact of coronavirus,” he wrote in emailed comments.

Which stocks are in focus?

What are other markets doing?

Gold futures US:GCJ20 gained 0.2% at $1,675.70 an ounce after initially soaring to a more-than-seven-year high on haven-related flows.

Asian stock markets plunged Monday, with Tokyo’s Nikkei NIK, +0.17% down 5.1% and Hong Kong’s Hang Seng HSI, +0.47% off 4.2% and the Shanghai Composite SHCOMP, +2.06% down 3%.

European equities also fell sharply, with London’s FTSE 100 stock index UKX, -0.70% finishing 6.6% lower and Germany’s DAX DAX, -0.69% falling 6.7%. Italy’s FTSE MIB I945, -1.08% plunged 9.4%.