Newly released data showed that 6.6 million Americans filed initial jobless claims last week, bringing the three-week total to a staggering 16.8 million and underscoring the mounting economic fallout from the COVID-19 pandemic.

In the week ending April 4, the number of people filing for U.S. unemployment benefits slightly decreased by 261,000 to 6,606,000, after setting a second straight record in previous week, the U.S. Bureau of Labor Statistics reported on Thursday.

"The very large spikes in weekly jobless claims, which were over 6 million for two consecutive months, suggests a much broader set of job closures in the short run," Michael Hicks, director of the Center for Business and Economic Research at Ball State University in Indiana, told Xinhua via email.

"The very rapid adoption of shelter-in-place orders by U.S. governors is clearly causing a significant reduction in employment across the states implementing it," Hicks said.

As COVID-19 continues to sweep across the country, over 40 states and the District of Columbia have ordered residents to stay at home unless necessary. Deborah Birx, coronavirus response coordinator for the White House Coronavirus Task Force, has recently discouraged Americans from visiting the grocery store and pharmacy.

Jared Bernstein, a senior fellow at the Center on Budget and Policy Priorities, noted that prior cumulative three-week peak is 2 million in late 1982. "Never seen anything like this and policy response must be commensurate," he said on Twitter.

"We estimated that about 28 million U.S. workers, or about 1 in 7 were at risk of losing jobs because they interacted directly with the public or other employees," Hicks said, adding that these are workers likely to be unemployed until the COVID-19 is "treatable or has a vaccine."

Hicks, however, noted that it is also possible that some workers will find work in other sectors (grocery and delivery stores) and for some businesses to reopen after acquiring sufficient personal protective equipment, or separating workers in an assembly line or factory.

The newly released number came after the figure spiked by 3 million to reach a record 3.3 million in the week ending March 21, and then surged by 3.34 million to reach 6.65 million in the week ending March 28, which was revised up 6,87 million.

The report also showed that the 4-week moving average, a method to iron out data volatility, increased by 1,598,750 to 4,265,500.

The advance seasonally adjusted insured unemployment rate was 5.1 percent for the week ending March 28, an increase of 3.0 percentage points from the previous week's unrevised rate, according to the report.

Hicks said job losses will propel the U.S. unemployment rate over 15 percent by the end of April, and "perhaps higher in later months."

As COVID-19 cases continue to climb, non-essential businesses, such as theaters, museums, gyms and shopping malls, are largely shut down, and restaurants and bars are asked to avoid in-person dining, effectively paralyzing the consumption-driven U.S. economy.

Former U.S. Federal Reserve Chairman Ben Bernanke said Tuesday that the U.S. economy could contract at a 30 percent annualized rate or more in the second quarter, noting that he doesn't see a rapid rebound.

"The critical factor in terms of how bad this is going to be, how much imprint it will leave on the U.S economy is its duration," he told a webinar hosted by the Washington-based think tank Brookings Institution. "The most important determinant of the duration is the public health response."

As of Thursday afternoon, over 450,000 confirmed cases have been reported across the United States, with death toll surpassing 16,000, according to a data tracking tool developed by the Center for Systems Science and Engineering at Johns Hopkins University.

President Donald Trump said at a White House briefing Wednesday that the number of new cases is "stabilizing," noting that soon "we'll be over that curve." He added there will be "some terrible days ahead."

Bernanke said he doesn't see the economy returning to a more normal state "until there's much greater confidence both among average people and at the level of governors and mayors that opening up the economy won't restart the crisis."