U.S. financial markets fell even further on Thursday, with the Dow Jones Industrial Average losing more than 2,350 points, almost 10%, in the biggest single-day decline since one of more than 22% in 1987's Black Monday crash.

The S&P 500 and Nasdaq similarly tumbled by 9.51% and 9.43%, with the S&P 500 joining the Dow in bear market territory.

Earlier in Thursday trading, the S&P 500 plummeted by more than 7%, triggering a temporary "circuit-breaker" trading halt for 15 minutes. When trading resumed just before 10 a.m., markets declined further. Thursday marked the second time the New York Stock Exchange has halted trading this week.

As markets reeled, the Federal Reserve announced a $1.5 trillion plan to help stabilize the financial system, but that appeared to have little effect.

"These changes are being made to address highly unusual disruptions in Treasury financing markets associated with the coronavirus outbreak," the Federal Reserve Bank of New York said in a statement.

Liz Ann Sonders, chief investment strategist at Charles Schwab, told ABC News Thursday there is a limit to what the Fed's actions can do in a situation like this.

“Even if the Fed lowers rates, it doesn’t get more tests out there, it doesn’t create a vaccine -- there is a limit to what Central Banks can do," she added. "This is not a financial crisis like what 2008 was -- this is a human and health crisis. So, more needs to be done at the local and national government level."

"We see the central banks are sort of pulling out all the stops, but it's not the elixir for what ails us," she added.

The sharp selloff comes after President Donald Trump announced late Wednesday that the U.S. was enacting a ban on certain travel from Europe to the U.S. for the next 30 days, calling for a series of stimulus measures to blunt the economic side effects of the virus. His measures appeared to only heighten investors' anxiety.

"The coronavirus pandemic has taken the stock market into bear market territory, and further declines are in the offing as the U.S. effectively hits the 'pause' button on the economy in an effort to curtail spread of the virus," according to Greg McBride, chief financial analyst at Bankrate. "Yes, there will be economic disruption, and an all-but-certain recession."

"Markets will undoubtedly overshoot to the downside, so it is more important than ever for investors to maintain their long-term perspective," he added. "Markets will recover sooner, and much faster, than the overall economy, and you cannot be sitting on the sidelines when that happens."

Futures on the Dow Jones Industrial Average and the S&P 500 were temporarily halted in premarket trading after plummeting more than the "limit-down" of 5%.

On Wednesday, the Dow entered bear market territory for the first time since the 2008 financial crisis.

As the volatility rages on and uncertainty abounds amid the ever-evolving COVID-19 situation, many analysts said the economic shock due to the pandemic will hopefully be short term.

"Historically, in pandemics, stocks have usually begun to recover as the number of new diagnosed cases stabilized, not necessarily even declined," Burt White, managing director and chief investment officer at LPL Financial, said in a commentary Thursday. "While this volatile environment is challenging, it can also present opportunities for suitable investors, as we still have confidence in the long-term fundamentals and prospects for the U.S. economy."

Experts at the Schwab Center for Financial Research urged everyday investors to "resist the urge to sell based solely on recent market movements."

"Selling stocks when markets drop can make temporary losses permanent. Staying the course, while difficult emotionally, may be healthier for your portfolio," the analyst team wrote in a commentary. "This doesn’t mean you should hold on blindly, but we suggest taking into account an investment’s future prospects and the role it plays in your portfolio, rather than being guided by noise and fear."

Sonders added that the financial blow on Wall Street likely will soon affect everyday people as well, noting that some of the biggest industry sectors, in terms of the percentage of total employed Americans, include hospitality and retail.

"I think when it hits the labor market data, that tends to really hit home for Main Street," Sonders added. "This is already going beyond being a Wall Street problem."