As nations grapple with new outbreaks and spiking death tolls from the coronavirus, a commonly available drug appeared Tuesday to offer hope that the most seriously ill could have a better chance of survival.

The pandemic has forced countries to impose lockdowns and tough restrictions on daily life and travel, but infections have surged as they eased these rules and reopened their economies. With no vaccine available and much still unknown about the virus, researchers in England announced the first drug shown to save lives.

The drug, called dexamethasone, reduced deaths by 35% in patients who needed treatment with breathing machines and by 20% in those only needing supplemental oxygen, researchers in England said. It did not appear to help less ill patients.

British Prime Minister Boris Johnson said the drug was the "biggest breakthrough yet" in treating the coronavirus, and top U.S. infectious disease expert Dr. Anthony Fauci called it "a significant improvement in the available therapeutic options that we have."

Britain is making dexamethasone available to patients on the country's National Health Service. The U.K. Department of Health said the drug had been approved to treat all hospitalized COVID-19 patients requiring oxygen, effective immediately. It said the U.K. had stockpiled enough to treat 200,000 patients.

"It's on almost every pharmacy shelf in every hospital, it's available throughout the world, and it's very cheap," said Peter Horby of Oxford University, one of the leaders of the trial that randomly assigned 2,104 patients to get the drug and compared them with 4,321 patients getting only usual care.

Since the virus emerged in China late last year and spread worldwide, there have been more than 8 million confirmed cases and over 441,000 deaths.

The U.S. death toll has exceeded 116,900, according to Johns Hopkins University. That surpasses the number of Americans who died in World War I, when 116,516 were killed - although both tolls are far from precise.

The U.S. has the most confirmed infections and deaths from COVID-19 in the world, and as parts of the economy have reopened in recent weeks, cases have surged in places like Texas, Arizona and Florida, where the virus has sidelined some members of a U.S. team that tracks hurricanes.

For most people, the virus causes mild or moderate symptoms, such as fever and cough. For some, especially older adults and people with existing health problems, it can cause more severe illness, including pneumonia and death.

Countries that appeared to have largely contained the virus are seeing new outbreaks.

In China, authorities have taken drastic action to contain an outbreak in Beijing that has infected more than 135 people. Most of the cases have been linked to the capital's Xinfadi wholesale food market, with several neighborhoods near it and another market locked down and thousands ordered to be tested. The city also has suspended sports games, closed entertainment venues and cut back domestic flights, among other measures.

New Zealand, which hadn't seen a new case in three weeks, was investigating after two women who flew in from London to see a dying parent were allowed to leave quarantine and drive halfway across the country before they were tested and found to be positive.

The reemergence of the virus in the country once praised for how it handled infections raised the specter that international air travel could trigger a fresh wave of contagion just as countries are reopening airports to stimulate tourism.

Canada and the U.S. will extend to July 21 an agreement to keep their border closed to nonessential travel, with many Canadians fearing cases arriving from the U.S.

"This is a decision that will protect people on both sides of the border as we continue to fight COVID-19," Canadian Prime Minister Justin Trudeau said.

The U.S. car industry was among the first to reopen, yet the virus began to spread again almost immediately - even with significant safety precautions in factories. Similar spikes have been seen after hair salons, day care centers and restaurants reopened.

Hula Hut, a large Tex-Mex restaurant in Austin, Texas, reopened in May but had to shut down again this month for six days after two employees tested positive for COVID-19 in quick succession.

Texas doesn't require restaurants to close after a positive test, but general manager Elias Chocalas said it gave time to sanitize Hula Hut repeatedly and get his employees tested.

"We follow all the steps and then to see that someone has gotten it is just disheartening," Chocalas said. "It just brought the realization that this is going to happen regardless of how safe we are."

Texas is among the states reporting spikes in cases, setting a single-day high with 2,622 new infections Tuesday and a record for COVID-19 hospitalizations for the eighth time in nine days, with 2,518.

"It does raise concerns, but there is no reason right now to be alarmed," Gov. Greg Abbott said, urging people to wear masks and stay home as much as possible.

The Republican said Texas' health care system can handle the surge as the nation's second-most-populated state pushes forward with reopening one of the world's largest economies.

Florida's confirmed cases also set a daily record, at almost 2,800. With hurricane season underway, the virus has spread to the team that operates the nation's hurricane hunter planes. Five employees at the team's Lakeland, Florida, base tested positive last week, forcing others into quarantine, National Oceanic and Atmospheric Administration officials said.

New cases in Arizona hit an alarming daily high of nearly 2,400 - almost double the previous record, health officials said. The state also reported 25 additional deaths, while hospital intensive care units were hovering around 80% capacity.

In Tennessee, the number of infected patients in hospitals has reached its highest level, at more than 400, Vanderbilt University researchers said. A surge in new cases and hospitalizations has led Memphis and Nashville to delay plans to reopen more businesses and increase capacities for restaurants and retail stores.

Nevada, where casinos reopened almost two weeks ago, has reported 379 new cases, its largest daily increase since May 22. Health officials said it can be partially attributed to delayed reporting but is also part of an upward trend in the last three weeks.

Elsewhere around the world:

- Record-high infections were registered in South Africa over the weekend, two weeks after businesses and houses of worship reopened. The country now has more than a quarter of the cases on the 54-nation African continent, with over 73,000.

- Egypt's health ministry reported 97 deaths Monday, the country's highest for a single day. Egypt, which has resisted a full lockdown, has over 46,000 COVID-19 infections and 1,672 deaths.

- Israel's steady rise in infections since restrictions eased last month has increased fears of what a top Health Ministry official said looked like the "beginning of a wave," with 200 new cases daily. That's a tenfold increase from a few weeks ago, and authorities warned of possibly reinstating strict lockdown measures.

- El Salvador, the most locked down country in Latin America, slowly began opening Tuesday after nearly three months of mandatory stay-at-home orders. Back were taxis and ride-sharing services, hair salons, and food delivery and takeout, but schools remained closed.

Hadjicostis reported from Nicosia, Cyprus, Rico reported from Atlanta and Pane reported from Boise, Idaho. Associated Press reporters around the world contributed.