Global stock markets and oil prices plunged on Monday, as novel coronavirus pneumonia continued to spread worldwide and investors braced for another volatile week in the markets.

The main stock indexes in London and Frandfurt and on Wall Street in New York fell about 7 percent, which triggered an automatic trade halt for 15 minutes on the US exchange. Trading later resumed and prices had slightly stabilized as of press time.

Stocks in Asia saw steep declines on Monday afternoon, and US futures had sunk on Monday morning, after oil prices plunged amid virus fears.

The outbreak has also hit production in many countries, disrupting supply chains and damaging tourism.

Japan's Nikkei stock index plunged below 20,000 on Monday for the first time since January last year, with stocks in Singapore, Australia, Hong Kong, Shanghai and Shenzhen also sinking.

US futures saw sharp declines on Monday morning. Futures on the Dow Jones Industrial Average plunged 1,255 points, pointing to an opening loss on Monday of about 1,300 points. S&P 500 futures and Nasdaq-100 futures also pointed to declines for the two indexes when they opened on Monday, CNBC reported.

The developments on Monday signaled more turbulence ahead after a roller-coaster week that saw the S&P 500 swing up or down more than 2.5 percent for four days straight, according to CNBC. It quoted Bill Maldonado, chief investment officer for the Asia-Pacific at HSBC Global Asset Management, as saying, "The uncomfortable truth ... for a lot of investors is that there's really nowhere easy to hide."

It also quoted analyst Adam Crisafulli, founder of Vital Knowledge Media, on Sunday as saying that crude oil "has become a bigger problem for markets than the coronavirus".

During Asian trading hours on Monday afternoon, the international benchmark Brent crude futures contract fell 28.74 percent to $32.26 per barrel after Saudi Arabia, the world's top oil exporter, said it would step up production beginning next month.

The Guardian reported that Brent's fall was its worst single-day decline since the start of the Gulf War in 1991.

According to Crisafulli, "It will be virtually impossible for the (S&P 500) to sustainably bounce if Brent continues to crater."

In addition, US West Texas Intermediate crude futures fell 30.77 percent to $28.58 per barrel.

On Friday, oil prices had plunged after the Organization of the Petroleum Exporting Countries and its allies failed to reach an agreement on proposed additional output reductions of 1.5 million barrels per day.

"As prices look set to continue cratering, some are warning about the impact on the broader economy," CNBC said.

OPEC and its allies also failed to reach an agreement on extending current production cuts under a deal that will expire on April 1. When the agreement expires, each nation will effectively have free rein over how much crude it pumps

Amid the coronavirus fears, Japan's economy slowed an annualized 7.1 percent in the October-December quarter, according to Reuters. That was worse than a Reuters forecast of a 6.6 percent contraction and the biggest fall since 2014.

The worse-than-expected decline has led to fears that Japan could see growth contract for two straight quarters－the definition of a recession.

Italy has locked down its northern region to contain the virus's spread, affecting more than 16 million people by banning them from moving in and out of the affected areas. Some other countries are also thinking about stringent measures such as social distancing.

On Sunday, Anthony Fauci, the head of the infectious diseases unit at the US National Institutes of Health, said on NBC's Meet the Press that after initial missteps distributing tests, there were to be 400,000 more tests available by Monday and 4 million by the end of the week.

He said Americans, especially those who are vulnerable, may need to stop attending big gatherings as the coronavirus spreads through US communities.

In the US, the virus has been reported in 34 states and the capital, with 565 cases and 21 deaths, CNN reported on Monday.

Six states in the US－California, Florida, Maryland, New York, Oregon and Washington－have declared states of emergency, granting their governors additional powers to fight the virus's spread.

The Associated Press reported that fences were being installed at an 11-acre site at the Port of Oakland, California, as US federal and state authorities prepared flights and buses to take the more than 2,000 passengers aboard the Grand Princess cruise liner to military bases or their home countries for a 14-day quarantine. The more than 3,500 people on the ship are from 54 countries. At least 21 people aboard have tested positive for the coronavirus.

In France, which has recorded more than 1,100 cases, the virus is spreading among members of the National Assembly, the lower house of the country's parliament. Four deputies have been infected, NBC News reported.

Indian authorities in the port city of Mangalore have turned away the MSC cruise ship Lirica, with 1,400 passengers, which was due to dock there, an official confirmed to the BBC. None of the passengers were believed to have virus symptoms.

The country's shipping ministry has issued an advisory that says no cruise ships from foreign countries can dock anywhere in India, as part of coronavirus preventive measures.

The Republic of Korea's President Moon Jae-in expressed guarded hope for the country's fight against the coronavirus on Monday, saying an ongoing downward trend in new infections could lead to a phase of stability.

The ROK launched a mask rationing system on Monday, under which citizens can buy at most two protective masks per week from pharmacies, on designated days of the week, Yonhap News Agency reported.

A special flight from the Democratic People's Republic of Korea carrying diplomats and other foreigners arrived in Russia's Far East city of Vladivostok on Monday, as the DPRK tightens a lockdown intended to fend off the coronavirus, according to AP.

Colin Crooks, the British ambassador to Pyongyang, tweeted on Monday that the British embassy there would remain open, while the German embassy and French Office were closing temporarily.