Washington — As President Trump signals his desire to restart the U.S. economy, Dr. Scott Gottlieb, his first commissioner of the Food and Drug Administration, is warning that society cannot return to normalcy as long as the coronavirus continues to spread in the nation's largest cities.

In a series of tweets Monday night, Gottlieb said it is vital for the country to end the spread of COVID-19, the coronavirus disease, and said the health care system cannot function and people can't return to work if they are "terrified of a virus raging uncontrolled." Gottlieb has been one of the most vocal advocates for aggressive government intervention to combat the virus.

"There's a strong and understandable desire to return to better times and a functioning economy," he wrote. "But it should not be lost on anyone that there's no such thing as a functioning economy and society so long as covid-19 continues to spread uncontrolled in our biggest cities."

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Gottlieb added that as long as the coronavirus "spreads uncontrolled, older people will die in historic numbers, middle aged folks doomed to prolonged ICU stays to fight for their lives, hospitals will be overwhelmed, and most Americans terrified to leave homes, eat out, take the subway, or go to the park."

So long as covid-19 spreads uncontrolled, older people will die in historic numbers, middle aged folks doomed to prolonged ICU stays to fight for their lives, hospitals will be overwhelmed, and most Americans terrified to leave homes, eat out, take the subway, or go to the park. — Scott Gottlieb, MD (@ScottGottliebMD) March 24, 2020

"The only way to return to a stable economy and restore our liberty is to end epidemic spread of covid-19," he continued. "We need a massive effort to offset the hardship of these efforts, and the public health costs they impose, as there are more than economic costs to measures we're taking."

Gottlieb said the country must choose to break the epidemic rather than let large numbers of people come down with the coronavirus.

"There's no easy return. We must accept a sober truth," he said. "This pathogen has altered history and changed our world. But it caught us at a time when we have the public health tools, technology, and know how to defeat it quickly and vanquish it for good. We must stay on the battlefield."

Earlier Monday, Mr. Trump seemed to question whether it was time to consider loosening restrictions enacted to flatten the number of new coronavirus cases. Public health officials have urged Americans to limit their social interactions and stay at home, and a growing number of states have ordered all nonessential businesses to close.

The measures have effectively brought the U.S. economy to a halt and left Congress scrambling to craft a massive stimulus package to lessen the pain inflicted on American workers and businesses.

But Mr. Trump told reporters the U.S. "will soon be open for business," and suggested Americans can follow public health guidance to limit the spread of the coronavirus while also returning to their normal lives.

"Our country wasn't built to be shut down," he said. "This is not a country that was built for this. It was not built to be shut down."

The Trump administration plans to reassess 15-day guidance issued last week when that clock runs out.