Coronavirus updates: 23-year-old college student dies from COVID-19

Around 4,000 people in South Australia have been ordered to quarantine as the Australian state grapples with a fresh COVID-19 outbreak.

South Australia authorities announced five new locally-transmitted cases on Tuesday, at least four of which were officially linked to a medi-hotel in the Parafield suburb of Adelaide, where travelers arriving from abroad are required to quarantine for 14 days. Authorities said the fifth case is expected to be connected to the Parafield cluster soon, which would bring the total number to 21.

"All of these people have either no symptoms or they are very mildly symptomatic, and they have been picked up early in the course of the disease," South Australia’s chief health officer, Prof. Nicola Spurrier, said at a press conference Tuesday.

Those who have been advised to isolate are all close contacts of the cluster from the quarantine hotel and are being contacted daily by health authorities to check for symptoms. Meanwhile, at least five schools have been closed as contact tracers work to contain the outbreak, according to Spurrier.

"We've decided to take a very, very cautious approach," she told reporters, later adding that "this is a very, very worrying situation."

Thousands of people have been tested for COVID-19 in South Australia in recent days. Spurrier urged people to only get tested if they are symptomatic or if they have recently visited the areas of concern.

"We do need to prioritize our testing across South Australia," she said.

There are currently 34 active infections in the state, including imported cases. The latest cluster is the first instance of community transmission in South Australia since April.

"I need to reiterate to the people of South Australia that we are not out of the woods yet," the state's premier, Steven Marshall, said at Tuesday's press conference. "We are just at the beginning stages of dealing with this particular very nasty cluster in Parafield. We are going to get through this. But we’re going to get through it with the cooperation of every single South Australian citizen."

Austrians awoke Tuesday morning with a new tough lockdown meant to curb the spread of the novel coronavirus.

Under the stricter measures, which will remain in place through Dec. 6, people in Austria are only allowed to leave their homes to buy groceries, to go to work if their jobs are deemed essential, to exercise outside, to go to the doctor or to help people who need assistance.

Schools across the Alpine nation have shuttered, as teaching will be done remotely during lockdown. Banks, basic food stores and pharmacies remain open but bars, hair salons, restaurants and other non-essential shops and services have been ordered closed.

"All of social and public life will be brought down to a minimum," Austrian Chancellor Sebastian Kurz said Monday, ahead of the new restrictions.

It's the second time since the start of the coronavirus pandemic that Austria has imposed a nationwide lockdown, amid rising infections across Europe. The Austrian Federal Ministry of Social Affairs, Health, Care and Consumer Protection has confirmed more than 208,000 cases of COVID-19 so far, including at least 1,741 deaths. Nearly 50,000 of those cases were reported in the past week alone.

Russia registered 442 deaths from COVID-19 in the last 24 hours, marking the country's highest single-day death toll from the disease since the pandemic began.

An additional 22,410 new cases of COVID-19 were also confirmed nationwide over the past day. Russia's cumulative total now stands at 1,971,013 cases with 33,931 deaths, according to the country's coronavirus response headquarters.

Moscow remains the epicenter of the country's outbreak and recent surge. More than a quarter of the newly confirmed cases -- 5,882 -- and nearly 17% of the new deaths -- 74 -- were reported in the capital, according to Russia's coronavirus response headquarters.

Despite the growing number of infections and deaths, Russian authorities have repeatedly said they have no plans to impose another nationwide lockdown.

The Eastern European country of 145 million people has the fifth-highest tally of COVID-19 cases in the world, behind only the United States, India, Brazil and France, according to a real-time count kept by Johns Hopkins University.

ABC News' Alina Lobzina contributed to this report.

There were 166,045 new cases of COVID-19 confirmed in the United States on Monday, according to a real-time count kept by Johns Hopkins University.

It's the fourth day in a row that the country has reported over 150,000 newly diagnosed infections. Monday's count is slightly less than the all-time high of 177,224 on Nov. 13.

An additional 995 fatalities from COVID-19 were also registered nationwide on Monday, down from a peak of 2,609 new deaths on April 15.

A total of 11,205,486 people in the United States have been diagnosed with COVID-19 since the pandemic began, and at least 247,220 of them have died, according to Johns Hopkins. The cases include people from all 50 U.S. states, Washington, D.C. and other U.S. territories as well as repatriated citizens.

Much of the country was under lockdown by the end of March as the first wave of pandemic hit. By May 20, all U.S. states had begun lifting stay-at-home orders and other restrictions put in place to curb the spread of the novel coronavirus. The day-to-day increase in the country's cases then hovered around 20,000 for a couple of weeks before shooting back up and crossing 100,000 for the first time on Nov. 4.