This story was reported by Catherine Carrera, Matthew Chayes, Candice Ferrette, Bart Jones, David Olson, Jean-Paul Salamanca, Joie Tyrrell and Dandan Zou. It was written by Olson.

New York is preparing for what Gov. Andrew M. Cuomo on Friday called "a dramatic increase" in testing for the coronavirus, raising the state's capacity to handle about 6,000 tests a day by next week.

That's more tests in a day than New York State had completed in the more than two months since the outbreak emerged in Wuhan, China.

"Testing is probably the single most important thing that we could be doing now," Cuomo said.

Cuomo said the ramped-up testing will result from 28 labs that work with the state coming online, after New York received the go-ahead from the federal government, following conversations with Vice President Mike Pence and President Donald Trump.

Cuomo is typically searing in his criticisms of Trump, but he praised him for giving the state the leeway. Trump, in a speech announcing a national emergency declaration, called his talk with Cuomo "a very good conversation."

New York City Mayor Bill de Blasio said of the emergency declaration at an afternoon news conference, that more involvement was needed from the federal government. "Hopefully, this is a step in the right direction," he said.

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The state's total of confirmed coronavirus cases rose to 421, Cuomo said, with 50 people, or 12% of those patients, hospitalized, and 18 of them in intensive care. New York had surpassed Washington, with 420 cases, as the state with the most people who tested positive for the virus, he said.

Long Island has 79 confirmed COVID-19 cases so far.

In New York City, there were 154 confirmed cases, the governor's office and de Blasio said Friday afternoon, up from 95 on Thursday. The latest borough-by-borough breakdown of cases was 35 in Manhattan, 24 in Brooklyn, 26 in Queens, 13 in the Bronx and five in Staten Island, he said. The number of people in preventive isolation in New York City was 1,747.

New York City's health commissioner, Dr. Oxiris Barbot, said 30 of those diagnosed with coronavirus are in hospitals and 21 of them are in intensive care.

Suffolk County Executive Steve Bellone announced Friday afternoon a ban on after-school activities and a suspension of civil-service exams and job fairs, as the number of confirmed coronavirus cases rose by 12 to a total of 28 in the county.

Eleven of those cases are in the Town of Southold, five are in Brookhaven, four in Huntington, three in Babylon, two in Islip, two in Smithtown, and one case in East Hampton.

Bellone also said the Suffolk police department is issuing an order that officers not go inside homes with emergency medical services workers when it involves an illness.

“We’re trying to limit exposure where we can, particularly for first responders,” he said.

Suffolk will deliver state-produced hand sanitizer to all the county’s nursing homes, he said.

Bellone had declared a state of emergency Thursday.

Earlier Friday morning, Nassau County Executive Laura Curran declared a state of emergency, which allows the county to access more resources to combat the virus, authorizes emergency spending, and permits the county to take other urgent actions.

One Nassau town and nine of 10 towns in Suffolk had declared a state of emergency.

Nassau's total of confirmed cases rose to 51, up 11 from the previous day, the state said. Curran had said earlier that 34 of those cases came from Hempstead, 10 from North Hempstead and 4 from Oyster Bay.

"As testing ramps up and increases, we expect that number to increase," she said.

Curran also said Nassau would close county-owned museums, recreational facilities, preserves and historic sites. The county also was closing the comptroller’s and county clerk’s offices, and the Traffic and Parking Violations Agency, to the public and temporarily stopping enforcement of its towing and boot programs. Beginning Monday, a reduced number of employees will report to county offices.

The Nassau state of emergency went into effect at 5 p.m. Friday, Curran said. Under law, it is effective for five days but can be renewed.

County-owned parks and golf courses, though, will remain open, and Curran encouraged residents to use them while practicing "social distancing," or not standing near others.

County Health Commissioner Dr. Lawrence Eisenstein said 13 residents of those who had tested positive by Friday morning were hospitalized, but only two were in critical condition, both people with underlying health conditions.

"The vast, overwhelming majority of cases are doing well," he said.

Many Long Island school districts are closing, but the majority remain open. Eisenstein addressed calls for a countywide school closure, saying experts advise closing schools is one of the least effective ways to control a pandemic. He added it can lead to unintended consequences, such as grandparents having to watch children, while the kids' parents are at work, potentially exposing the grandparents to the virus.

Earlier Friday, Cuomo said he also was wary of closing all schools. Critically needed health care workers would have to stay at home to watch their children, other parents would also be forced to miss work, and kids wouldn't have access to in-school nutrition programs.

At least two major mosques on Long Island announced they were canceling their traditional religious services on Friday because of concerns over coronavirus.

The Diocese of Rockville Centre said Friday that Catholics do not have to attend Mass for the next three weekends, because of coronavirus concerns.

'A fluid situation'

In his daily coronavirus update, Cuomo said that, with some schools around New York closing because of COVID-19 concerns, the state will waive the rule that schools must be in session for at least 180 days to qualify for full state funding.

He said the state also would waive a seven-day waiting period for unemployment insurance if a layoff or loss of pay is due to a quarantine or other effect of the virus, and said the Public Service Commission would bar utilities from cutting service to someone who didn’t pay their bill for virus-related reasons.

Cuomo said officials haven’t decided whether to go ahead with the April 28 statewide presidential primary or the March 24 Queens borough president election.

“This is a fluid situation, so we’re dealing with all of these issues as they come up,” he said.

He said he is concerned about people knocking on doors asking for signatures on election nominating petitions, and officials are discussing how to address that.

“This is not the best time to be sending people door to door,” he said. “It’s the exact opposite of what we’re trying to do.”

Cuomo said that as the number of cases continues to rise, he also is worried about the health care system’s ability to care for all who will require hospitalization. In the future, some elective surgeries may have to be canceled or postponed to free up beds for those ill with COVID-19, he said.

Drive-thru testing

Cuomo spoke earlier Friday at the launch of New York's first effort of "drive-thru testing" for coronavirus in New Rochelle, the city in Westchester County at the center of the outbreak in the state, saying the new approach will help to expand capacity to detect more cases.

He said the facility will be able to handle about 200 cars per day, where "you drive in your car and the medical staff comes to you."

“It is not only faster and easier," he said. "It’s also smarter and safer because you’re not exposing people to a person who may be positive.”

Cuomo said New Rochelle residents, and those who are most vulnerable to COVID-19 — older adults, people with compromised immune systems and those with underlying health conditions, especially respiratory diseases — will be given priority for testing, followed by others who live in Westchester County.

“You want to find positive cases because you want to be able to isolate those positive cases and then find out who that person may have been in touch with so you can get them the assistance they need," he said.

Cuomo said the epidemic has directly impacted his own family, revealing that his daughter is in a 14-day precautionary quarantine because “she came in contact with someone who was in a hot spot, who we didn’t know whether or not that person was positive.”

Cuomo asked New Yorkers to gird for many months of lives altered by the virus.

“I don’t believe this is going to be a short-term issue," he said. "I think we’re looking at a matter of months, and people should start to calibrate that into their expectations.”

But there is reason for optimism, said Michael J. Dowling, president and CEO of New Hyde Park-based Northwell Health, which is running the mobile testing site in partnership with the state.

“This is an issue that will be beaten,” Dowling said. “We will win this. It may take some time.”

Also Friday, the state Department of Financial Services announced an emergency regulation that bars New York health insurers from charging for emergency-room services with co-payments, deductibles and coinsurance.

“This emergency regulation will allow New Yorkers to get tested without worrying about cost, providing a measure of relief as the COVID-19 situation evolves,” department Superintendent Linda A. Lacewell said in a statement.

School closings

By Friday afternoon, many school districts across Long Island were sending notices to residents to let them know that schools would close for days or even weeks for deep cleaning or as a precautionary period to help prevent the spread of the virus.

Among districts that had closed Friday but had not announced further closures were Sachem, Sewanhaka and Valley Stream Central.

Closing Friday and Monday were the Oysterponds district for "a cautious investigation" on the recommendation of the Suffolk County Department of Health Services. Closing for those two days, only as precautionary measures, were Hauppauge, Port Washington and Southold, said officials in those school districts.

Connetquot, Mattituck-Cutchogue and Rocky Point are closing Monday, according to district officials.

Connetquot school officials stated in a notice that while the buildings are closed to students Monday, “Teachers will prepare educational opportunities for our students to be worked on independently, in order to be proactive and prepared, if we are forced to close due to confirmed cases of COVID-19.”

Central Islip, Farmingdale, Levittown and North Merrick will close Monday and Tuesday to clean the schools, their superintendents said in notices to residents. The Lawrence schools are closed through Wednesday.

Other districts opted to close all of next week. Those include Bethpage, Cold Spring Harbor, Elwood, Huntington, Long Beach, Roslyn, South Huntington, Three Village and the Diocese of Rockville Centre.

“Please know that this decision was not made lightly and we recognize the impact such a closure will have on our families,” Three Village Superintendent Cheryl Pedisich said in a note posted on the district's website.

Half Hollow Hills and Commack will be closing for two weeks, starting Monday, according to official notices from those schools.

School officials in the Brentwood district, which has more than 18,900 students, posted a notice on the district's website saying buildings and grounds crews will clean and sanitize all school buildings. The district expects to reopen Monday, the notice said.

Some private Catholic high schools, which do not report directly to the diocese, said they were moving to online instruction starting next week. They include Kellenberg and Chaminade high schools, run by the Marianist brothers, and St. Anthony’s High School, run by the Franciscan Brothers.

“We are all being cautious and are responding with a backup plan since social distancing seems to be the recommended way to get a handle on this virus,” said Brother Kenneth Hoagland, principal of Kellenberg.

In New York City, de Blasio did not close city schools, but said schoolchildren would be spaced from each other under social-distancing efforts to prevent spread. Attendance was 68 percent on Friday, compared with 85 percent a day earlier, he said.

Asked about contingency plans for teachers who live in suburbs like Long Island, if they can't come to work because their children are in schools that canceled classes, New York City Schools Chancellor Richard Carranza said the city would use substitute teachers and bring in personnel in related fields from other city agencies.

De Blasio said the city was in the process of developing a plan to accommodate teachers and others who are over 50 and medically vulnerable to coronavirus.