ROME (AP) — Sweeping travel bans accelerated across the globe on Thursday, walling regions apart, keeping people inside their homes and slowing the engines of commerce in an effort to stem the viral pandemic unfolding around the world.

President Donald Trump, who had downplayed the virus for weeks, suddenly struck a different tone, delivering a somber Oval Office address announcing strict rules on travel from much of Europe to begin this weekend. The State Department followed with an extraordinary warning to Americans to "reconsider travel abroad" as well.

The European Union quickly slammed Trump's "unilateral" decision, declaring that the coronavirus pandemic is a "global crisis, not limited to any continent and it requires cooperation rather than unilateral action."

The virus detected three months ago in China has produced crippling outbreaks in Asia, Europe and the Mideast, ignited global financial panic and in the last week has seen dizzying developments that are erupting by the hour.

Those include an official designation of "pandemic" from the World Health Organization, a dramatic halt to much travel between the United States and 26 European countries, and infections being announced in rapid-fire pace by Hollywood stars, sports luminaries and political leaders as well as ordinary folks on cruise ships. All of this is coming against a backdrop of crashing world economies that left not only Wall Street investors but people from all walks of life hurting.

"It's similar to what you might think of as an infectious disease equivalent of a major earthquake that's going to shake us for weeks and weeks," said Dr. Jeff Duchin a top public health official for the Seattle area, which has one of the biggest U.S. coronavirus outbreaks.

Around the world, nursing homes emptied of visitors to protect the elderly, who are especially vulnerable to the new virus.

More than 126,000 people in more than 110 countries have been infected by the new virus. The vast majority are in just four countries: China and South Korea — where new cases are declining — and Iran and Italy, where they are not. More than 4,600 people have died worldwide.

In California, the governor advised cancelling any gatherings of more than 250 people, as well as any smaller meetings where people must be closer than 6 feet (2 meters).

In Italy, the center of Europe's epidemic, new restrictions closed restaurants, cafes and retail shops Thursday after the prime minister imposed a nationwide lockdown on personal movement earlier in the week. Grocery stores, pharmacies and outdoor markets were allowed to operate, as were newspaper kiosks.

Rosanna Farina, whose family has run a newspaper kiosk in Rome's historic center since the 19th century, was torn on whether it was worth staying open.

"So few people are out and about. People are terrorized," she said, wearing a scarf around her face. "I'd rather be home. I'm worried, even if I'm keeping a distance."

Even remote Mount Everest closed for business. Chinese mountaineering officials cancelled spring climbs from their side of the mountain, while on the other side in Nepal, operators say cancellations were pouring in.

Across the U.S., where cases now number more than 1,300, a sense of urgency was pervasive.

Schools emptied of students and workplace cubicles went vacant. A rite of spring, college basketball's March Madness, was to proceed in empty arenas, while the NBA decided it won't play professional basketball won't play at all. Joyous, booze-filled, green-splashed celebrations of St. Patrick's Day were called off across the U.S. and Ireland. TV shows taped without audiences, rush-hour crowds in New York subway cars disappeared and families hunkered down, wondering what would come next.

"If we avoid each other and listen to the scientists, maybe in a few weeks it will be better," said Koloud 'Kay' Tarapolsi of Redmond, Washington, who has two children whose schools closed Thursday.

As the pandemic grips Europe and the U.S., it continues to ebb in China, where the first cases of COVID-19 emerged in December. It reported a record low of just 15 new cases Thursday. So far more than three-fourths of China's patients have recovered.

Most people infected by the new virus have only mild or moderate symptoms, such as fever and cough, though symptoms can be severe, including pneumonia, especially in older adults and people with existing health problems. Recovery for mild cases takes about two weeks, while more severe illness may take three to six weeks, WHO says.

German Chancellor Angela Merkel warned her nation that, over time, two-thirds of the country could become infected since people do not have immunity to COVID-19.

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

Double Oscar winner Tom Hanks said he and his wife Rita Wilson tested positive. Australian officials say the couple are in a Queensland hospital and their close contacts need to self-quarantine.

In Italy, soccer club Juventus said defender Daniele Rugani tested positive. In Iran, the senior vice president and two other Cabinet ministers were reported to have been diagnosed with COVID-19. In Spain, the equality minister was diagnosed and her husband, a deputy prime minister, was in quarantine.

Asian shares plunged Thursday, following a drop of 1,464 points of the Dow Jones Industrial Average, putting the index 20% below its record set last month and into fearsome territory Wall Street calls a "bear market."

"There's a real feeling that we don't know where this ends," said Brad McMillan, chief investment officer for Commonwealth Financial Network.

In Europe, governments and airlines were blindsided by Trump's travel ban to the United States.

Britain and Ireland were exempt, despite imposing far fewer restrictions in response to the virus than many EU countries, raising questions about the coherence of the American policy. Trump has properties in both nations.

Trump accused Europe of not acting quickly enough to address the "foreign virus" and claimed that U.S. clusters were "seeded" by European travelers.

In response, EU Council President Charles Michel and the European Commission President Ursula von der Leyen said the coronavirus pandemic is a "global crisis, not limited to any continent and it requires cooperation rather than unilateral action."

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Hinnant reported from Paris. Contributing to this report were Associated Press writers Maria Cheng in London; Jamey Keaten in Geneva; Samuel Petrequin in Brussels; John Leicester in Paris; Colleen Barry in Soave, Italy; Frances D'Emilio in Rome; Rachel La Corte in Olympia, Washington; Chris Grygiel and Lisa Baumann in Seattle; and Adam Geller, David B. Caruso and Theo Wayt in New York.

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The Associated Press receives support for health and science coverage from the Howard Hughes Medical Institute's Department of Science Education. The AP is solely responsible for all content.

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