Of the 21 new positive COVID-19 cases, Monmouth County has three, bringing that county's total to eight.
Bergen County has two cases, bringing its total to 15 -- by far the most in the state -- with eight in Teaneck alone.
Other counties with two new cases each are Essex, Hudson, Middlesex, Morris and Hudson, officials said.
"For many in the state, this is an anxious time," said Gov. Phil Murphy, who urged citizens to let facts and science guide their thinking.
Murphy said he will continue to press the federal government for much-needed health-care supplies like respirators, masks and other protective gear.
"We will not be shy to push. . . to meet the needs of New Jersey,'' Murphy said. "We will get through this."
Other reminders from Murphy: Washing your hands with soap and water for 20 seconds, staying six feet away from others, self-quarantining if you feel ill and calling elder family members, neighbors and friends to check on them.
"This is not a time to panic,'' Murphy said. "Exercise common sense. Know that we will get through this."
Murphy recommended on Thursday that all public gatherings of more than 250 people in the state be cancelled. These include concerts, sporting events and parades. He urged keeping a six-foot buffer between others.
Nearly 360 school districts have closed and eventually all will be shut down, the governor said.
"You've got to do it responsibly. You've got to do it right,'' Murphy said.
State officials had an incomplete county-by-county breakdown, but here are the counties with one new presumptive positive cases on Friday: Ocean, Mercer, Burlington and Passaic.
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