(CNN) With new guidelines from the federal government, some governors have rolled out plans to begin lifting measures in place battling the spread of the coronavirus -- but other officials say it's still too early.

In Florida, residents flocked to Jacksonville beaches after officials announced a soft opening Friday night allowing for recreational activities for several hours each day. In Texas and Minnesota, state leaders announced they'd be lifting some of the measures in place in the coming days -- still requiring residents to keep a distance and avoid big crowds.

Jacksonville Beach Public Information Officer Tonya Tator told CNN on Saturday, "Everyone has done a great job at adhering to the social distancing and all other rules on Jacksonville Beach today."

South Carolina appears to be following suit. Restrictions on beach access as well as retail stores will be lifted next week, according to a report from The Post and Courier newspaper in Charleston, citing Gov. Henry McMaster's Chief of Staff Trey Walker. The governor is expected to announce the eased restrictions Monday.

But some health experts and medical groups have warned the US is still behind in its testing capacity -- a key factor in the country's reopening process to help determine and track just how many people are infected.

In a three-part guideline released this week, the White House said states can enter the first phase toward reopening once they see a continued decrease over two weeks.

As of Saturday night, there were more than 734,552 confirmed cases in the US and at least 38,835 people had died, according to Johns Hopkins University.

Trump blames governors

President Donald Trump on Saturday repeatedly blamed governors for not making full use of coronavirus testing capacity in their states, even as several Democrat and Republican governors said they are facing shortages of critical supplies to conduct tests.

"They don't want to use all of the capacity that we've created. We have tremendous capacity," Trump said. "They know that. The governors know that. The Democrat governors know that. They're the ones that are complaining."

Trump, who has said governors will call the shots on when to reopen their state, has said the states with the lowest number of cases could begin reopening "literally tomorrow."

An influential model of the virus that's often cited by the White House says some states with a low number of cases could begin lifting measures starting May 4. Those include Vermont, West Virginia, Montana, and Hawaii.

Others, including Iowa, North and South Dakota, Nebraska, Utah, Arkansas, and Oklahoma, may need to wait until late June or early July.

"Actual decisions by states to relax social distancing should be informed by meeting critical metrics closer to these dates, including a very low number of estimated infections in the community -- less than one estimated infection per 1 million people," the Institute for Health Metrics and Evaluation at the University of Washington (IHME), where the model was created, said in a news release.

Montana, still recording one of the lowest numbers of cases in the country, says it's not prepared to reopen.

"Even the gating criteria (of two straight weeks with new cases slowing down) that the president put out yesterday -- we haven't met those criteria," Gov. Steve Bullock said Friday.

Meanwhile, governors of 31 states and Washington, DC have ordered or recommended that public schools remain closed through the end of the school year, CNN reporting reveals. Though he's allowing the state's beaches to reopen, Florida Gov. Ron DeSantis announced Saturday that public schools will remain closed through the school year.

Cuomo says New York numbers are dipping but still 'overwhelming'

The state of New York is seeing hospitalization, ICU and intubation numbers down, Gov. Andrew Cuomo said at a press conference Saturday.

But that doesn't mean the state is near reopening. New York is "barely" in a stable position, Cuomo said.

"If you look at the past three days you could argue that we are past the plateau and we're starting to descend, which would be very good news," Cuomo said. "We're not at the plateau anymore but we're still not in a good position."

Testing is the most important thing, Cuomo said, because it is "how you monitor the rate of infection," and testing "informs the calibration."

The state did 500,000 tests in a month, but that is "only a fraction of what you need," Cuomo said, calling on the federal government for more coordination and assistance.

New Jersey Gov. Phil Murphy said his state continues to aggressively ramp up testing capabilities. Murphy went on to say prematurely opening a state could be dangerous.

"Anybody out there who thinks that let's just open the place up will lead to lower infections, lower hospitalizations and lower fatalities is being completely and utterly irresponsible," he said.

Air Force Academy cadets, spaced 8 feet apart, listen to a commencement address by Vice President Mike Pence Saturday.

In Colorado on Saturday, Gov. Jared Polis wore a mask as he greeted Vice President Mike Pence, who arrived to give the commencement address at the Air Force Academy. Pence told the graduates the American people have met the challenge of the coronavirus" with courage, resilience and strength."

On April 3, the White House announced CDC guidance that Americans wear "non-medical cloth" face coverings. Pence did not wear a mask upon arrival in Colorado. Trump has said he won't wear a mask, either.

Canada border will stay closed, Trudeau says

Also Saturday, Canadian Prime Minister Justin Trudeau announced the border to the US will remain closed until at least May 19, except for essential traffic.

"Canada and the United States have agreed to extend, by another 30 days, the border measures that are currently in place. This is an important decision and one that will keep people on both sides of the border safe," Trudeau said at a press conference in Ottawa.

Trudeau said essential goods and services will continue to across the border, including medical workers and supplies.

On Wednesday, Trump had said this "will be one of the early borders to be released."

Where measures are being lifted

In Jacksonville, Mayor Lenny Curry said people on newly opened beaches are taking social distancing seriously and their actions are helping flatten the curve of coronavirus cases.

"This is not a return to normal life yet, but a way to responsibly include limited outdoor exercise," Curry said.

Texas Gov. Greg Abbott issued an executive order Friday easing some measures next week -- ordering state parks to reopen by Monday but directing residents to wear face coverings, keep a distance and stay in groups of five people or less.

Texas has more than 18,000 reported infections, according to a tally by Johns Hopkins University, making it one of the states with the most cases.

The governor also directed retail stores to begin reopening April 24 and instead deliver products to customers' cars and homes. He said the process of reopening the state will happen gradually and will be guided by medical experts.

US Democratic Rep. Lloyd Doggett, criticizing the governor's decision, said there will be a "cost in lives of doing it prematurely when there's so many questions about the accuracy of testing, of so many dangers from ignoring social distancing. I find his orders troubling."

In Minnesota, Gov. Tim Walz signed an order allowing many outdoor activities -- including golfing, boating, hunting and biking -- to resume Saturday morning, as long as residents follow social distancing guidelines, avoid crowded spaces and stay close to home.

"The only way this is going to work even with something like golf or shooting ranges or trails, is if we follow those, washing our hands, stay home (guidelines). If you're sick, cough into your sleeve, wear a mask." Walz said in a news conference Friday.

New coronavirus outbreaks kept being reported Saturday.

The Ohio Department of Rehabilitation and Correction started isolating inmates after more than 1,300 inmates tested positive across three facilities, department spokeswoman JoEllen Smith told CNN in an email Saturday.

In Virginia, at least 25 residents of Department of Juvenile Justice's Bon Air Juvenile Correctional Center tested positive, DJJ said in a news release.

US still behind on testing, expert says

Experts have for long said one of the major determining factors behind governors' decisions to reopen their economies should be testing, and medical experts continue to insist the country is behind.

Pence said Friday the White House coronavirus task force believes the US has the testing capacity for states to begin easing their measures -- the first of three phases in the federal guide of reopening the country.

JUST WATCHED Fauci: There will be enough tests to begin reopening US Replay More Videos ... MUST WATCH Fauci: There will be enough tests to begin reopening US 03:56

Dr. Tom Frieden, the former director of the US Centers of Disease Control and Prevention, says the country's current number of conducted tests -- less than 150,000 a day -- are not nearly enough.

"If we were just testing the highest priority people and nobody else, we'd need about three times as many tests," Frieden told CNN. But as the US is testing lower priority people as well, the country would need 10 to 20 times more tests than that, Frieden said.

Harvard researchers said in an article that the US needs to conduct at least 500,000 tests for Covid-19 every day to be able to successfully open the economy and stay open. Currently, just 150,000 tests per day are completed.

About 20% those tests have been positive, according to the Harvard researchers Dr. Ashish Jha, Dr. Thomas Tsai and Benjamin Jacobson. The World Health Organization has suggested that an adequate test positive rate should be between 3% and 12%.

And earlier this week, the Association of American Medical Colleges sent a letter to the government's task force saying labs are facing critical shortages.

"Laboratories across the country are working day and night to expand testing capacity but are severely hampered by shortages of needed reagents, swabs for testing, PPE, and specialized equipment designed by companies to be used with their own machines," it said.

More protests over stay-at-home orders

But despite the continued uncertainty over the country's testing capacity, governors face a new pressure: angry residents demanding an end to stay-at-home orders over concerns of the economic impact.

In Texas on Saturday, a day after the governor announced a phased reopening of the state, hundreds gathered in front of the State Capitol in Austin for a "You Can't Close America" rally.

In Indianapolis, protesters gathered outside the home of Gov. Eric Holcomb to protest his stay-at-home order, which has been extended until May 1.

In New Hampshire, a crowd formed outside the State House and urged Gov. Chris Sununu to lift emergency orders.

In Maryland, people in cars paraded through Annapolis, honking their horns and holding signs, to encourage Gov. Larry Hogan lift restrictions.

More are planned for the coming days, including in Wisconsin, Kansas and Missouri.

Ben Dorr, who organized the group Wisconsinites Against Excessive Quarantine, told CNN affiliate WFRV he fears economic destruction.

"Hundreds of thousands of workers are out of work. Hundreds and thousands of small family businesses are being destroyed right now under this quarantine, under this lockdown," Dorr told the news station.

"I notice there are a lot of protests out there," Trump said Saturday. "And just think that some of the governors have gotten carried away. You know you have a lot of people don't have to be told to do what they are doing, they've really been doing everything we've asked them."