Washington: Over 16,000 confirmed cases were reported in a single day in the US on Thursday as the total number of COVID-19 patients soared to 85,088, the highest for any country, according to data compiled by Worldometer.

The United States surpassed China (81,285) and Italy (80,589) in terms of number of people infected with the novel coronavirus.

According to Worldometers, the website that records confirmed cases of infection and deaths globally, the US by Thursday night had 85,088 individuals infected with coronavirus, of which 16,877 were added just in a single day. A week ago, the number of confirmed cases were 8,000. It has dangerously surged 10 times in the span of a week.

With at least 263 deaths, the US also reported most number of fatalities due to the contagion on a single day on Thursday. At least 1,290 Americans have died due to coronavirus so far. Over 2,000 coronavirus cases were reportedly in a serious condition. The number of confirmed cases as well as the deaths due to COVID-19 are likely to increase substantially in the coming days.

In China, from where it all originated, 3,287 people have died due to coronavirus pandemic while Italy has recorded 8,215 such deaths.

US President Donald Trump attributed the spike in the confirmed cases of coronavirus to the large-scale testing of the deadly disease.

"I think it's a tribute to our testing," he said, adding "no one knows what the numbers are in China".

Vice President Mike Pence said it is important for hospitals and labs testing the samples to report back to the Centre for Disease Control and Federal Emergency Management Agency so that the government has full visibility to provide the President with the best counsel.

The Abbott Laboratory, he said, submitted to Food and Drug Administration a national request for approval of a point-of-care test. This would be the kind of test where one could go to a doctor and get the test done and have the results in no more than 15 minutes.

According to Dr Deborah Brix, coordinator for the White House Coronavirus Task Force, 55 per cent of all new cases continue out of the New York - New York Metro area. This includes New Jersey as well, she said and expressed concern over the coronavirus spread.

"At the same time, 19 of the 50 states that had early cases, but have persistently low level of cases and at this point have less than 200 cases," she said.

In an in interview with CNN, Dr Anthony Fauci, America's top infectious disease expert said it is difficult to tell where the pandemic will go and how long it will last in the US.

This is the relative percentage of asymptomatic infection and it "influences everything," he said. It influences transmission, contact tracing, and the measures that the authorities need to take. That's why the most important thing to do now is to conduct widespread testing and collect more data, he asserted.

He called for ratcheting up the current level of contact tracing and testing. "We've got to do it better than we are now".

The prestigious Johns Hopkins University, which is also recording all cases of coronavirus, reported 83,836 cases in the United States, ahead of China and Italy.

Dr Brix said so far the US has done 5,50,000 tests.

"We are still running somewhere about 14 per cent overall. That means 86 per cent of the people with significant symptoms because remember you had to have a fever and symptoms to get tested at this point. So still 86 per cent are negative," she said.

These are really important facts for the American people, Dr Brix said.

She was critical of some of the modelling studies which had said that there would be 500,000 deaths in the UK and 2.2 million deaths in the US. "They have adjusted that number in the UK to 20,000. Half a million to 20,000. We are looking into this in great detail to understand that adjustment," she said.

"When people start talking about 20 per cent of a population getting infected, it's very scary but we don't have data that matches that based on the experience," Dr Brix said.

She assured Americans that there is no shortage of essential medical supplies including ventilators and ICU beds.

China bans foreigners, flights cut

Meanwhile, China reported more than 50 imported cases of the coronavirus on Friday, hours after announcing a ban on foreigners entering the country.

In recent weeks China's tally of infections has dwindled dramatically, with only a handful of domestic patients each day. But just as the country appears to bring the outbreak under control, nations around the globe have been battling to control soaring numbers of infections in new hotspots.

There were another 55 new infections in China on Friday, the National Health Commission said, with one local infection and 54 imported cases from overseas.

Beijing has been racing to control the number of infections being brought into the country - mostly Chinese nationals returning home from overseas, including large numbers of students abroad.

On Thursday Beijing announced dramatic measures to curb arrivals into the country, including reducing the number of international flights, limiting the capacity on board to 75 percent, and imposing a ban on foreigners entering China.

Non-nationals living in China with valid visas and resident permits will be blocked from returning to the country after midnight on Friday night, the foreign ministry said in a statement.

The ministry said it was a "temporary measure that China is compelled to take in light of the outbreak situation." Diplomats and the crew of international airlines and vessels will still be permitted to enter.

Flights in and out of China will also be capped at just one route a week to each country, including for international airlines.

The tally of cases brought into China from abroad climbed to 595 on Friday, health officials said.

A series of strict measures had already been put in place to try and stem the wave of infections coming in.

All Beijing-bound international flights have been diverted to other urban centres, where passengers will first be screened for the virus.

Many Chinese cities including Beijing and Shanghai have also imposed a compulsory 14-day quarantine for all arrivals from abroad.

There were nearly 1,100 return international passenger flights scheduled to come to China this week.

There were another five deaths on Friday, according to the National Health Commission - all in the province of Hubei where the virus first emerged late last year.

In total 81,340 people have been infected in China, and the outbreak has claimed 3,292 lives.

Switzerland virus cases top 10,000

Switzerland on Thursday joined the small group of countries to declare more than 10,000 officially-recorded cases of COVID-19, as it launched plans to start tracking crowd build-ups through mobile phone data.

The health ministry said 10,661 people in the Alpine country have tested positive for the new coronavirus - nearly 1,000 more than a day earlier - while 161 people have died.

Switzerland, which is among the countries that have conducted most COVID-19 tests per capita, is the fifth country in Europe to pass 10,000 officially-recorded cases.

Switzerland's Italian-speaking southern region of Ticino, which borders hard-hit northern Italy, is the worst-affected of its 26 cantons, with 393 cases per 100,000 people.

Around two-fifths of Switzerland's COVID-19 deaths have occurred in Ticino.

The first case of the new coronavirus was confirmed in Switzerland on February 24.

Since then, "91,400 tests have been carried out for COVID-19, of which 14 percent were positive," the Federal Office of Public Health said.

Those testing positive have ranged in age from under one to 102, with a median age of 52 years old, and a near-even split of men and women.

The Swiss government has ordered the closure of schools and all places of leisure, including restaurants, bars and non-food shops.

Last Friday it went further, banning all gatherings of more than five people, while anyone standing closer than two metres to others risks a fine.