World Health Organization director Tedros Adhanom Ghebreyesus said that for the foreseeable future, there would be "no return to the old normal" as COVID-19 cases rise by one million in five days and the total number of coronavirus infections around the world hit 13 million on Monday.

The pandemic has now killed more than half a million people in six-and-a-half months, and Ghebreyesus said the virus remains public enemy number one and noting that "too many countries are headed in the wrong direction."

"If basics are not followed, the only way this pandemic is going to go, it is going to get worse and worse, and worse. But it does not have to be this way."

Tedros noted that the most recent surge of COVID-19 cases come from the Americas, with the U.S. and Brazil accounting for more than a third of global deaths from the disease.

California shuts down again

On Monday, California shut down again as COVID-19 cases are on the rise in about 40 U.S. states.

Governor Gavin Newsom, a Democrat, ordered bars closed and restaurants, movie theaters, zoos and museums statewide to cease indoor operations. Newsom said churches, gyms and hair salons must close in the 30 hardest-hit counties.

The state's two largest school districts, Los Angeles and San Diego, with a combined 706,000 students and 88,000 employees, said in a joint statement they would hold online-only classes for the new term, citing "vague and contradictory" science and public health guidelines.

The union representing Los Angeles teachers applauded the strategy, saying it was backed by 83 percent of its 18,000 rank-and-file members responding to an informal online poll last week.

"In the face of the alarming spike in COVID cases, the lack of necessary funding from the government to open schools safely, and the outsized threat of death faced by working-class communities of color, there really is no other choice that doesn't put thousands of lives at risk," United Teachers Los Angeles said in a separate statement.

The online-learning decision puts the two districts at odds with U.S. President Donald Trump, who has threatened to punish school systems that refuse to reopen classrooms by withholding federal funding or even removing their tax-exempt status.

Education Secretary Betsy DeVos kept up the pressure on Sunday in a televised appearance, saying children need to return to their classrooms both for the sake of their own educational development and so that their parents can more easily return to the workplace.

"We know that children get the virus at a far lower rate than any other part of the population," DeVos told CNN. "There is nothing in the data that would suggest kids being back in school is dangerous to them."

House Speaker Nancy Pelosi sharply criticized the Trump administration for advocating a return to school in the fall, accusing Trump of "messing with" children's health and saying federal guidelines on reopening schools amid the coronavirus outbreak should be mandatory.

UK could see 120,000 deaths in a second wave

As the U.S. grapples with more than 3.3 million confirmed cases, it is still seeing huge increases in a first wave of COVID-19 infections. In some other places, such as the Australian city of Melbourne and Leicester in England, are implementing a second round of shutdowns and others are to tighten social distancing measures again amid growing worries about a second wave.

In UK, a report commissioned by the government's chief scientific adviser Patrick Vallance warned that a second wave in Britain this winter could eclipse the current outbreak resulting in up to 120,000 deaths in hospitals alone between September and June next year. The modelling does not include deaths in care homes or the wider community, and assumes no government action to prevent a fresh surge in cases.

Britain has seen almost 45,000 deaths so far in the first wave, the highest toll in Europe and third only to the U.S. and Brazil. The latest predictions are based on an assumption that the R rate – which measures how many people an infected person is expected to infect – rises to 1.7 from September. Scientists also modelled for a lower increased R rate of 1.5, which would lead to 74,800 deaths. The R rate is currently between 0.7 to 0.9 across the country.

The group of 37 scientists involved in the report said the government needed to prepare immediately and called for "intense preparation" this month to prevent the country's state-run National Health Service (NHS) from being overwhelmed.

That includes work to minimize community transmission, a public information campaign and ensuring enough protective equipment for frontline medical and social care staff. The government's test, trace and isolate program also needed to be scaled up, along with surveillance and ensuring at risk individuals, health and care workers get flu jabs.

(With input from agencies)