An international team of 13 scientists researching the origins of COVID-19 arrived Thursday in Wuhan, China, where the novel coronavirus was first discovered, according to the World Health Organization.

"The experts will begin their work immediately during the 2 weeks quarantine protocol for international travelers," the WHO wrote on Twitter.

All team members had to be tested for COVID-19 again in Singapore before flying to China. The polymerase chain reaction (PCR) tests were all negative, but two IgM antibody tests returned positive results. Those two scientists remain in Singapore as they are retested, according to the WHO.

A total of 965,000 workers in the United States filed jobless claims last week, the U.S. Department of Labor said Thursday, an increase of 181,000 from the prior week.

The Labor Department also said that more than 18 million people were still receiving some form of unemployment benefits through all government programs for the week ending Dec. 26. For the comparable week in 2019, that figure was just above 2 million.

The weekly unemployment tally has fallen since peaking at 6.9 million in March but still remains elevated by historical standards.

The pre-pandemic record for weekly unemployment filings was 695,000 in 1982.

That record has been broken every week since late March.

As of last month, the unemployment rate in the U.S. was 6.7%. It was 3.5% last February.

-ABC News’ Catherine Thorbecke contributed to this report

This week’s national ensemble forecast released by the U.S. Centers for Disease Control and Prevention predicts that 16,200 to 29,600 more Americans will likely die from COVID-19 in the week ending Feb. 2.

The national ensemble estimates a total of 440,000 to 477,000 deaths from the disease will be reported nationwide by that date.

Nearly all U.S. metro areas with over 500,000 people are in "full resurgence" of COVID-19, the White House coronavirus task force said in its latest report, obtained by ABC News Wednesday.

In the report, dated Jan. 10, the task force said the fall/winter surge has had nearly twice the rate of rise in COVID-19 cases as the spring and summer surges.

Several states, including Arizona, California, Florida, Georgia, Louisiana, New Mexico and South Carolina, are also in "full pandemic resurgence," the report stated.

Only "aggressive mitigation" can "match a more aggressive virus," and Americans must take more precautions, "moving beyond what worked in the summer to more layered mitigation," the report stated.

The task force recommended uniform mask implementation and "strict physical distancing." Without that, "epidemics could quickly worsen as more transmissible variants spread and become predominant," it warned.

ABC News' Josh Margolin and Brian Hartman contributed to this report.

With 4,327 confirmed deaths on Tuesday -- the deadliest day of the pandemic so far -- Tuesday’s death toll equaled about one American dying every 20 seconds.

The national average of daily cases is also at a record high, with 246,000 new cases every day.

In the last week, 22 states and Washington, D.C., have reported a record seven-day average of daily cases.

Since the beginning of the pandemic, at least 22.8 million Americans have contracted COVID-19 -- meaning about one in every 14 Americans has tested positive.

California has the most hospitalizations of any state with more than 22,000 patients, followed by Texas, New York, Florida and Georgia.

Arizona, Alabama and Nevada currently hold the highest hospitalizations rates per million people in the country.

ABC News’ Arielle Mitropoulos contributed to this report.