LONDON (AP) — British officials are considering tougher coronavirus restrictions as the number of hospitalized COVID-19 patients surpasses the first peak of the outbreak in the spring.

Authorities are blaming a new, more transmissible variant of the virus, first identified in southeast England, for the soaring infection rates. An area home to almost half of the people in England is under tight restrictions on movement and everyday life in an attempt to curb the spread of the virus. Nonessential shops are shut along with gyms and swimming pools, indoor socializing is barred and restaurants and pubs can only offer takeout.

Prime Minister Boris Johnson plans to hold a meeting of his COVID-19 crisis committee later Tuesday. Health Secretary Matt Hancock is scheduled to update Parliament on Wednesday on whether more areas will be put into Tier 4 — the top level of lockdown measures — and whether the restrictions could be tightened even further.

Hospitals in the worst-hit areas of London and southern England are becoming increasingly overstretched, with ambulances unable to unload patients at some hospitals because all beds are full. A growing number of National Health Service staff are off work because they are sick with the virus or self-isolating.

England had 20,426 coronavirus patients in hospitals as of Monday morning — the last day for which figures are available — compared to its previous high of 18,974 on April 12. Britain has recorded more than 71,000 confirmed coronavirus deaths, the second-highest death toll in Europe after Italy.

Steve Hams, a chief nurse at Gloucestershire Hospitals NHS Foundation Trust in western England, said medical staff were becoming “increasingly exhausted.”

“We felt during April that there would be an end to this. But actually, we’re now seeing a third peak so trying to keep our colleagues and our teams going through this time is just incredibly difficult,” he told the BBC.

Dr. Sonia Adesara, an emergency-room doctor in London, said “doctors and nurses are having leave cancelled, they’re doing extra shifts, they’re working extra long hours but its an extremely serious situation.”

“The situation is untenable and I think we are very close to becoming overwhelmed,” she said.

Some scientists are urging Johnson’s Conservative government to postpone plans to reopen schools next week after the Christmas break. The government plans to test students regularly for the virus and 1,500 armed forces personnel have been called in to support schools organize the testing.

Andrew Hayward, a professor of infectious diseases epidemiology at University College London, said the fast-spreading virus variant meant that for U.K. schools to reopen, other sectors would have to close.

“We’re going to have to have increased, strict restrictions in other areas of society to pay for that,” he said.

Simon Stevens, chief executive of the NHS, said health care workers were back in “the eye of the storm” as they had been in the spring.

Stevens said the coronavirus vaccines provided hope, and estimated that all vulnerable people in Britain could be inoculated against the virus by late spring 2021. So far, more than 600,000 people in the U.K. have been given a shot of a vaccine developed by U.S. drugmaker Pfizer and German firm BioNTech, out of a population of 67 million.

Officials and medics hope U.K. regulators will soon authorize a second coronavirus vaccine for use in Britain. The Medicines and Healthcare Products Regulatory Agency is assessing a vaccine made by AstraZeneca and Oxford University.