WASHINGTON – President Donald Trump on Thursday laid out his vision for what he called the "next phase" in the war on the coronavirus pandemic that is sweeping the country.

In a letter to the nation's governors, Trump said he and his administration planned to develop criteria to "help classify counties with respect to continued risks posed by" the deadly coronavirus. He said the use of "robust surveillance testing" will allow local governments to track the spread of the virus.

Counties would be divided into three low, medium and high "risk" levels, the president wrote. These categories will be accompanied by "new guidelines for state and local policymakers to use in making decisions" about whether to maintain, decrease, or increase their social distancing guidelines.

The president has made no secret of his desire to see U.S. businesses reopen, even as the virus is infecting thousands of people every day across the country. Trump has set upon the date of Easter, April 12, as the one by which he hopes to see large parts of the country "roaring" back into business.

On Thursday, Vice President Mike Pence said that "a range of recommendations" would be presented to Trump over the weekend "for going forward. The president has made it clear that, in his words, he wants to open the country up. But we're going to do that responsibly," Pence told reporters at the White House.

Public health experts say that attempting to reopen businesses and loosen social distancing restrictions in a matter of weeks could mean tens of thousands of additional infections that could have been prevented by an extended campaign of mitigation. Trump, however, has suggested that experts who recommend extending the campaign are motivated by a desire to defeat him politically, and not by the desire to protect Americans from the life-threatening COVID-19 disease.

The White House has yet to release the new guidelines. But the very notion that risk during a contagion can be different from one county to another appears to contradict the basic health advice Trump's own experts are issuing.

White House health advisor Dr. Anthony Fauci said Thursday that the United States "can start thinking about getting back to some degree of normality when the country as a whole turns that corner" of reducing the spread of the coronavirus outbreak.

There are 3,141 counties or county equivalents in the United States, according to the U.S. Geological Survey.

As of Thursday, more than 81,000 Americans had been diagnosed with COVID-19, the disease caused by the coronavirus --- a higher number of infections than any other nation. More than 1,100 have died from it.

The Senate passed a massive $2 trillion relief bill Wednesday night to help individuals and businesses forced to suspend operations because of statewide stay-at-home orders and a national 15-day campaign to slow the spread of the virus. The House is expected to pass the bill Friday.

The relevant part of Trump's letter is below.

In furtherance of this shared goal, my administration is working to publish new guidelines for state and local policymakers to use in making decisions about maintaining, increasing, or relaxing social distancing and other mitigation measures they have put in place. This is what we envision: Our expanded testing capabilities will quickly enable us to publish criteria, developed in close coordination with the Nation's public health officials and scientists, to help classify counties with respect to continued risks posed by the virus. This will incorporate robust surveillance testing, which allows us to monitor the spread of the virus throughout the country. Under these data-driven criteria, we will suggest guidelines categorizing counties as high-risk, medium-risk, or low-risk. With each passing day, our increasingly extensive testing capabilities are giving us a better understanding of the virus and its path. As testing gives us more information about who has been infected, we are tracking the virus and isolating it to prevent further spread. This new information will drive the next phase in our war against this invisible enemy.

Trump's reliance on surveillance testing appears to ignore the fact that the U.S. currently does not have a national surveillance testing system in place.

The massive relief bill passed by the Senate on Wednesday contains $500 million to modernize public health data collection by the Centers for Disease Control and Prevention. Language in the bill says the CDC must report its progress on developing a "surveillance and data collection system" to Congress within the next 30 days.

On Thursday, Dr. Deborah Birx, coordinator of the White House coronavirus task force, said there are some examples of states where surveillance testing has been done using the same platform as flu surveillance, but she did not identify the states.

The plan outlined by the president also does not take into account the likely impact of opening some areas of the country while keeping others closed. Public health experts say this can actually contribute to the spread of pandemics by causing people in search of goods and services to travel from closed-down areas with high infection rates to more open areas with lower rates.

Asked about this on Thursday, Birx said she believes Americans "will understand where the virus is and where it isn't, because we'll have the testing, and they will take appropriate precautions as they move in and out of spaces."

And while the White House appears ready to lean heavily on the idea of surveillance testing, Trump himself rejected the idea of testing everyone in the country who should be tested, and then quarantining all infected individuals before permitting everyone else to go back to work.

Asked about broad testing nationwide at a news conference on Wednesday, Trump grew visibly frustrated. "We can go to certain states [that] have virtually no problem or a very small problem. …We don't have to test the entire state. I think it's ridiculous. We don't have to do it. A lot of those states could go back right now, and they probably will."

Coronavirus infections have been reported in all 50 states and the District of Columbia.