GENEVA (AP) — The World Health Organization declared Wednesday that the global coronavirus crisis is now a pandemic as U.S. stocks plunged into bear market territory and several American cities joined European counterparts in banning large gatherings.

By reversing course and using the charged word "pandemic" that it had previously shied away from, the U.N. health agency sought to shock lethargic countries into pulling out all the stops.

"We have called every day for countries to take urgent and aggressive action. We have rung the alarm bell loud and clear," said Tedros Adhanom Ghebreyesus, the WHO chief.

"All countries can still change the course of this pandemic. If countries detect, test, treat, isolate, trace and mobilize their people in the response," he said. "We are deeply concerned by the alarming levels of spread and severity and by the alarming levels of inaction."

After downplaying the threat of the virus for days, U.S. President Donald Trump was considering a national disaster declaration and new travel advisories. He was scheduled to deliver an Oval Office address to the nation Wednesday night.

In Italy, soccer club Juventus said defender Daniele Rugani tested positive and in the U.S., the battle to contain the epidemic prompted the NCAA to announce its championship basketball tournament would be played later this month without fans. Several other U.S. college and professional sports events have been either cancelled or ordered played in empty venues.

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Iran and Italy are the new front lines of the fight against the virus that started in China, the WHO said.

"They're suffering but I guarantee you other countries will be in that situation soon," said Dr. Mike Ryan, the WHO's emergencies chief.

For the global economy, virus repercussions were profound Wednesday, with increasing concerns of wealth- and job-wrecking recessions. U.S. stocks wiped out more than all the gains from a huge rally a day earlier as Wall Street continued to reel.

The Dow Jones Industrial Average dropped 1,464 points, bringing it 20% below its record set last month and putting it in what Wall Street calls a "bear market." The broader S&P 500, which professional investors care more about, is just 1 percentage point away from falling into bear territory and bringing to an end one of the greatest runs in Wall Street's history.

Wall Street's plunge followed a steep decline by markets across Asia, and was spurred in part by concerns over whether any economic response from the Trump administration will be effective.

WHO officials said they thought long and hard about labeling the crisis a pandemic — meaning a new virus causing sustained outbreaks in multiple regions of the world.

The risk of employing the term, Ryan said, is "if people use it as an excuse to give up."

But the benefit is "potentially of galvanizing the world to fight."

Underscoring the mounting challenge: The case count outside China has multiplied 13-fold over the last two weeks to over 118,000, with the disease now responsible for 4,291 deaths, WHO said.

With officials saying that Europe has become the new epicenter, Italy's cases soared again, to 12,462 infections and 827 deaths — numbers second only to China.

"If you want to be blunt, Europe is the new China," said Robert Redfield, the head of the U.S. Centers for Disease Control and Prevention.

In response to the mounting crisis, Italy announced that all shops and businesses except pharmacies and grocery stores would be closed nationwide beginning Thursday and designated billions in financial relief to cushion economic shocks from the virus, its latest efforts to adjust to the fast-evolving crisis that silenced the usually bustling heart of the Catholic faith, St. Peter's Square.

In Iran, by far the hardest-hit country in the Middle East, the senior vice president and two other Cabinet ministers were reported to have been diagnosed with COVID-19, the illness caused by the virus. Iran reported another jump in deaths, by 62 to 354 — behind only China and Italy.

Italian Premier Giuseppe Conte said it was necessary to "go another step″ in toughening the already unprecedented travel and social restrictions that took effect Tuesday by shuttering pubs, restaurants, hair salons, cafeterias and other businesses that can't operate with a meter (yard) of space between workers and customers.

"In this moment, all the world is looking at us for the number of infections, but also ... see great resistance," Conte said on Facebook Live.

These measures are on top of travel and social restrictions that imposed an eerie hush on cities and towns across the country.

Still, the effectiveness of travel restrictions and quarantines will likely drop substantially as COVID-19 spreads globally, making it impossible for countries to keep the virus out. Health officials will also need to be more flexible in their coordinated response efforts, as the epicenters are likely to shift quickly and dramatically — as demonstrated by the recent eruptions in Iran and Italy.

Earlier, Conte emphasized fighting the outbreak must not come at the expense of civil liberties, suggesting that Italy is unlikely to adopt the draconian quarantine measures that helped China push down new infections from thousands per day to a trickle and allowed its manufacturers to restart production lines.

China's new worry is that the coronavirus could re-enter from abroad. Beijing's city government announced that all overseas visitors will be quarantined for 14 days. Of 24 new cases reported Wednesday, five arrived from Italy and one from the United States. China has had over 81,000 virus infections and over 3,000 deaths.

For most, the coronavirus causes only mild or moderate symptoms, such as fever and cough. But for a few, especially older adults and people with existing health problems, it can cause more severe illnesses, including pneumonia. More than 121,000 people have been infected worldwide and over 4,300 have died.

But most people recover. People with mild illness recover in about two weeks, while more severe illness may take three to six weeks, the WHO says.

In the Mideast, most of the nearly 10,000 cases are in Iran or involve people who traveled there. Iran's semiofficial Fars news agency said they include Vice President Eshaq Jahangiri. Iran's ministers for cultural heritage, handcrafts and tourism, and for industry, mines and business were also infected, the agency said.

Italy's government announced Wednesday it was dedicating 25 billion euros (nearly $28 billion) to boost anti-virus efforts and soften economic blows, including delaying tax and mortgage payments by families and businesses.

Britain's government announced a 30 billion-pound ($39 billion) economic stimulus package and the Bank of England slashed its key interest rate by half a percentage point to 0.25%.

Normal life was increasingly upended, with Pope Francis live-streaming prayers from the privacy of his Vatican library as police barred access to St. Peter's Square, emptying it of tens of thousands of people who attend the weekly papal address. In Denmark, Prime Minister Minister Mette Frederiksen announced that all schools, preschools and universities will close as of Monday.

And in the U.S., the caseload passed 1,000, and outbreaks on both sides of the country stirred alarm. Officials in Seattle announced that public schools would close for about 53,000 students and large gatherings were banned in San Francisco and in Washington state, the hardest-hit U.S. state, with 29 deaths.

The virus upended the U.S. presidential campaign, with U.S. Vice President Joe Biden and Sen. Bernie Sanders canceling primary election rallies Tuesday and leaving open the possibility that future campaign events could be impacted. Trump's campaign insisted it would proceed as normal, although Vice President Mike Pence conceded future rallies would be evaluated "on a day to day basis."

And at a Congressional hearing in Washington Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Disease, sounded an alarm: "Bottom line, it's going to get worse."