ST. PETERSBURG, Fla. >> With the United States grappling with the worst coronavirus outbreak in the world, Florida hit a grim milestone today, shattering the national record for a state’s largest single-day increase in positive cases.

Deaths from the virus have also been rising in the U.S., especially in the South and West, though still well below the heights hit in April, according to a recent Associated Press analysis of data from Johns Hopkins University.

“I really do think we could control this, and it’s the human element that is so critical. It should be an effort of our country. We should be pulling together when we’re in a crisis, and we’re definitely not doing it,” said University of Florida epidemiologist Dr. Cindy Prins.

Adm. Brett Giroir, a member of the White House coronavirus task force, called mask-wearing in public, which has been met with resistance in some U.S. states, “absolutely essential.”

Giroir, the assistant secretary at the Health and Human Services Department, told ABC’s “This Week” today that “if we don’t have that, we will not get control of the virus.”

President Donald Trump wore a mask in public for the first time Saturday, something Democratic House Speaker Nancy Pelosi said today showed he has “crossed a bridge.”

Pelosi told CNN’s “State of the Union” that she hopes it means the president “will change his attitude, which will be helpful in stopping the spread of the coronavirus.”

In Florida, 15,299 people tested positive, for a total of 269,811 cases, and 45 deaths were recorded, according to state Department of Health statistics.

California had the previous record of daily positive cases — 11,694, set on Wednesday.

The numbers come at the end of a grim, record-breaking week as Florida reported 514 fatalities — an average of 73 a day. Three weeks ago, the state was averaging 30 deaths a day.

Researchers expect deaths to rise in the U.S. for at least some weeks, but some think the count probably will not go up as dramatically as it did in the spring because of several factors, including increased testing.

Meanwhile, countries in Eastern Europe were also facing rising waves of coronavirus infections, leading to riots in Serbia, mandatory face masks in Croatia and travel bans or quarantines imposed by Hungary.

“We see worrisome signs about an increase in the number of cases in the neighboring countries, Europe and the whole world,” said Gergely Gulyas, Hungarian Prime Minister Viktor Orban’s chief of staff. “Now, we have to protect our own security and prevent the virus from being brought in from abroad.”

Hungarian authorities said today they have sorted countries into three categories — red, yellow and green — based on their rates of new coronavirus infections, and will impose restrictions, including entry bans and mandatory quarantines, depending on which country people are arriving from.

Serbia, where health authorities are warning that hospitals are almost full due to the latest surge, reported 287 new infections on Sunday, although there have been increasing doubts about the accuracy of the figures. Officially, the country has over 18,000 confirmed infections and 382 deaths since March. Sunday’s report of 11 coronavirus deaths was the country’s second-highest daily death toll.

Serbian police clashed with anti-government protesters for four nights last week, demonstrations that forced the Serbian president to withdraw plans to reintroduce a coronavirus lockdown. Many of the increasing infections have been blamed on crowded soccer matches, tennis events and nightclubs.

In Bulgaria, authorities reintroduced restrictions lifted a few weeks ago because of a new surge in cases.

Albania also has seen a significant increase in infections since mid-May, when it eased lockdown measures. The Balkan nation reported 93 new cases, over twice as many as the highest daily figures in March and April, and the health ministry called the situation at the main infectious disease hospital “grave.”

“Don’t lower vigilance and respect hygiene rules,” Albanian health authorities urged.

Croatia, whose island-dotted Adriatic Sea coast is a major tourist destination, is making wearing masks mandatory in stores beginning Monday.

Yet the numbers of infections in Eastern Europe pale in comparison to daily coronavirus reports from India, South Africa and Brazil, whose virus-denying president has tested positive.

India, which has the most cases after the United States and Brazil, saw a record surge of 28,637 cases reported in the past 24 hours. Authorities also announced a weeklong lockdown beginning Tuesday in the key southern technology hub of Bangalore, where the offices of top tech companies like Microsoft, Apple and Amazon are located.

South Africa has reported over 10,000 new daily cases for several days in a row, including 13,497 new infections announced Saturday night. Johannesburg’s densely populated Soweto township is one of the virus hot spots. With over 264,000 cases and 3,971 deaths, South Africa accounts for over 40% of all the reported coronavirus cases in Africa.

Meanwhile, in Taiwan, which kept its coronavirus outbreak to a few hundred cases, an annual film festival wrapped up with an awards ceremony this weekend where actors and others lined up for photo shoots with no social distancing, and participants didn’t wear masks.