(CNN) Officials in California and Florida -- two states where coronavirus cases are jumping -- are taking different approaches toward reopening amid spikes in infections.
Florida Gov. Ron DeSantis told the reporters that there's no going back to stricter measures, while California Gov. Gavin Newsom hinted that on Wednesday he'll tighten restrictions, especially at beaches, this Independence Day weekend.
At least 19 states have paused or rolled back their reopening plans in response to a surge in new infections.
California has had more than 222,000 coronavirus cases -- about half of which are in Los Angeles County -- and on Tuesday announced 6,367 cases, the second highest total for the state since the pandemic began. In Los Angeles County there were reports of 2,779 new cases.
As the holiday weekend looms, Newsom warned that family gatherings are the greatest concern.
Family gatherings where households mix with extended family, tend to be a place where people let their guard down, the governor said.
"It's not just bars, not just out in the streets with people protesting, and the like," Newsom said.
The governor of the Golden State, who ordered bars in seven counties to close over the weekend, said he will announce more restrictions on Wednesday.
Newsom has repeatedly promised that reopening the state comes with the ability to "toggle back" if necessary.
Responding to a reporter's question about the beaches being closed in Los Angeles County for the Independence Day weekend, the governor hinted that state beaches could be part of his announcement.
In Florida, DeSantis assured reporters that his state can deal with the uptick in cases and it's not necessary to shut down shops and restaurants.
"We're not going back, closing things," he said. "I mean, people going to business is not what's driving it. I think when you see the younger folks, I think a lot of it is just more social interactions and so that's natural."
DeSantis' message to Floridians, particularly the younger ones: Protect the vulnerable.
"You have a responsibility not to come into close contact with folks who could be more vulnerable," he said.
A top US health official at a US Senate committee hearing made another plea for Americans -- especially younger ones -- to wear masks to curb the spread of the coronavirus as case numbers surge across much of the country.
It is "critical" that Americans "take the personal responsibility to slow the transmission of Covid-19 and embrace the universal use of face coverings," Dr. Robert Redfield, director of the US Centers for Disease Control and Prevention, said Tuesday.
"Specifically, I'm addressing the younger members of our society, the millennials and the Generation Zs -- I ask those that are listening to spread the word," he said.
The CDC urges everyone to wear a cloth face cover in public, primarily in case the wearer is unknowingly infected but does not have symptoms. Dr. Deborah Birx, the White House coronavirus task force coordinator, also has said there's growing evidence masks could help prevent the wearer from becoming infected, too.
The US has reported more than 2.6 million cases of the virus and at least 127,322 deaths, according to Johns Hopkins University. State and local leaders have said case rates have been rising in much of the country, driven in part by gatherings, both in homes and in places like bars -- which some experts have called the perfect breeding ground for the virus.
Fifteen states reported recording their highest seven-day averages of cases on Monday, according to JHU data. Of them, 10 have no statewide mask requirements -- Alabama, Alaska, Arizona, Florida, Idaho, Montana, South Carolina, Tennessee, Texas and Wyoming.
"Masks are extremely important," the head of the National Institute of Allergy and Infectious Diseases, Dr. Anthony Fauci, said Tuesday at the same Senate committee hearing. "It's people protecting each other. Anything that furthers the use of masks, whether it's giving out free masks or any other mechanism, I am thoroughly in favor of."
Among the states pausing or rolling back their reopening plans is Texas, where bars have been ordered shut.
Miami-Dade Mayor Carlos Gimenez told CNN he will be signing an order closing restaurants in the county nightly at midnight. Gimenez said that not complying with the order is a second-degree misdemeanor and violators can be fined and spend up to 180 days in jail.
The nation's rising case count has had ripple effects internationally. The European Union, which had shut its external borders because of coronavirus, agreed Tuesday to a list of 14 nations from which it will now accept travelers. The United States isn't on it, because its current Covid-19 infection rate is too high, the EU said.
New York, New Jersey and Connecticut are now asking people traveling from eight more states to self-quarantine upon arrival -- bringing their list to 16 -- because of coronavirus concerns.
The tri-state travel advisory, first issued last week, applies to anyone coming from a state with a positive test rate higher than 10 per 100,000 residents over a seven-day rolling average or a state with a 10% or higher positivity rate over a seven-day rolling average, the three Northeastern states have said.
The latest advisory, updated Tuesday, adds California, Georgia, Iowa, Idaho, Louisiana, Mississippi, Nevada and Tennessee to that list.
That's in addition to the list's incumbents: Alabama, Arkansas, Arizona, Florida, North Carolina, South Carolina, Utah and Texas.
The list requires people arriving from those states to quarantine for 14 days.
In New York, violators could be subject to a judicial order and mandatory quarantine, with fines of $2,000 for the first violation, $5,000 for the second violation, and $10,000 if harm is caused, Gov. Andrew Cuomo said.
New Jersey's governor said the state's health commissioner could choose to pursue unspecified punishments; Connecticut's governor has described his state's advisory as voluntary but considered it "urgent guidance."
Massachusetts announced Tuesday it is doing something similar. All arriving travelers, including returning residents, must self-quarantine for 14 days -- unless they're coming from seven Northeastern states, Gov. Charlie Baker said.
Those exempted states are Rhode Island, Connecticut, New Jersey, New York, Vermont, Maine and New Hampshire, Baker said. Essential workers also are exempt, he said.
Massachusetts also announced there were no Covid-19 related deaths on Tuesday, the first time in months zero deaths were reported.
The rethinking of how to safely reopen the US comes as 36 states have showed an upward trend in average new daily cases -- an increase of at least 10% -- over the last seven days, as of Tuesday, according to data from Johns Hopkins.
These states are: Alabama, Alaska, Arizona, Arkansas, California, Colorado, Delaware, Florida, Georgia, Idaho, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maine, Michigan, Mississippi, Missouri, Montana, Nevada, New Mexico, North Carolina, Ohio, Oregon, Pennsylvania, South Carolina, Tennessee, Texas, Utah, Vermont, Washington, West Virginia, Wisconsin and Wyoming.
Two states saw average daily cases decline more than 10% over those seven days: New Jersey and Rhode Island.
Chinese researchers have announced a recently discovered type of swine flu, but scientists around the world say that the virus does not appear to currently pose an immediate global health threat.
The G4 virus, which is genetically descended from the H1N1 swine flu that caused the 2009 pandemic, was described in a study published in the Proceedings of the National Academy of Sciences on Monday.
G4 already appears to have infected humans in China. In Hebei and Shandong provinces, both places with high pig numbers, more than 10% of swine workers on pig farms and 4.4% of the general population tested positive in a survey from 2016 to 2018.
Dr. Angela Rasmussen, a virologist at Columbia University's public health school who was not involved in the study, warned the public not to "freak out."
"Our understanding of what is a potential pandemic influenza strain is limited," Rasmussen posted on Twitter on Monday.