Tokyo and other areas of Japan may enter a state of emergency as COVID-19 infections continue to climb.

"The number of people infected with the novel coronavirus has not gone down, but rather has remained high in Tokyo and the neighboring prefectures," Japanese Prime Minister Yoshihide Suga said at a press conference Monday. "With that in mind, we thought we needed to send a stronger message."

Suga did not say when a state of emergency would go into effect but that the "details will be decided quickly." The announcement is expected to come before the end of the week.

Declaring a state of emergency would give the governors of those respective regions the authority to ask residents for cooperation in efforts to stem the spread of the virus. There are currently no legal ramifications for non-compliance.

Suga's predecessor, Shinzo Abe, declared a nationwide state of emergency relatively early in the pandemic in April, which lasted for a month. At that time, residents were asked to reduce person-to-person contact by 80% and to practice "jishuku," or "self-restraint," by staying at home and closing non-essential businesses.

Suga has said any upcoming state of emergency will be implemented in a "limited and focused" manner, leading some to speculate that the demands won’t be drastic. Restrictive measures could also disrupt preparations for the 2020 Summer Olympics in Tokyo, which was postponed to this year.

During Monday's press conference, Suga also pledged to speed up efforts to approve COVID-19 vaccines and to begin immunizing the country's senior citizens, health care workers and nursing home employees in late February.

COVID-19 infections soared in Tokyo over the holidays. On New Year's Eve, the Japanese capital reported over 1,300 newly confirmed cases for the first time in a single day. Nationwide, more than 245,000 cases have been confirmed since the start of the pandemic, including at least 3,645 deaths, according to the latest data from the Japanese Ministry of Health, Labour and Welfare.

Japan also recently detected several confirmed cases of the new, more contagious variant of the novel coronavirus that was first identified in the United Kingdom last month.

ABC News' Anthony Trotter contributed to this report.

A new variant of the novel coronavirus identified in South Africa is "even more of a problem" than the highly contagious strain spreading rapidly in the United Kingdom, according to British Health Secretary Matt Hancock.

"I’m incredibly worried about the South African variant, and that’s why we took the action that we did to restrict all flights from South Africa," Hancock said in an interview Monday on BBC Radio 4's "Today" program.

"This is a very, very significant problem," he added, "and it’s even more of a problem than the U.K. new variant."

Last month, the U.K. introduced a ban on travelers who have been in or transited through South Africa in the last 10 days due to an "increased risk" from the country's variant, called 501Y.V2. The travel ban does not apply to British or Irish nationals, U.K. visa holders and permanent residents, but they must self-quarantine.

The new rule comes as the U.K. grapples with a new, more contagious variant of the novel coronavirus that was identified in Kent in September. The strain, called B117, is currently prevalent in London and other parts of southeast England. It was also confirmed in the United States for the first time on Tuesday.

The South Africa variant was detected in the U.K. for the first time last week, linked to a contact of someone who had been in South Africa.

South African scientists say 501Y.V2 emerged after the first epidemic wave in a severely affected metropolitan area, Nelson Mandela Bay, located on the coast of South Africa's Eastern Cape province.

"This lineage spread rapidly, becoming within weeks the dominant lineage in the Eastern Cape and Western Cape provinces," researchers wrote in a scientific paper published last month. "Whilst the full significance of the mutations is yet to be determined, the genomic data, showing the rapid displacement of other lineages, suggest that this lineage may be associated with increased transmissibility."

South Africa, a nation of 57 million people, has reported more than 1.1 million confirmed cases of COVID-19 since the start of the pandemic, including at least 29,577 deaths. The country makes up for nearly 40% of all confirmed COVID-19 cases in Africa, a continent of 1.2 billion people, according to the latest data from the Africa Centers for Disease Control and Prevention.

The U.K., an island nation of 66 million people made up of England, Scotland, Wales and Northern Ireland, has reported more than 2.6 million confirmed cases of COVID-19 since the start of the pandemic, including at least 75,024 deaths, according to the latest data from the U.K. government. A count kept by Johns Hopkins University shows the U.K. currently has the sixth-highest total of diagnosed cases in the world.

Rollout of a COVID-19 vaccine developed by England's University of Oxford and British-Swedish pharmaceutical company AstraZeneca began in the United Kingdom on Monday morning.

Brian Pinker, an 82-year-old dialysis patient, was the first person in the country -- and the world -- to receive the newly approved vaccine outside of a clinical trial, according to a press release from National Health Service (NHS) England. He told reporters that he felt "pretty good" after getting the shot at Churchill Hospital in Oxford, England.

"I am so pleased to be getting the COVID vaccine today and really proud that it is one that was invented in Oxford," Pinker, who was born and raised in Oxford, said in a statement released by NHS England. "The nurses, doctors and staff today have all been brilliant and I can now really look forward to celebrating my 48th wedding anniversary with my wife Shirley later this year."

Trevor Cowlett, an 88-year-old music teacher and father of three, and Dr. Andrew Pollard, director of the Oxford Vaccine Group and chief investigator into the clinical trial of the shot, were also among the first to get the jab Monday.

"It was an incredibly proud moment for me to have received the actual vaccine that the University of Oxford and the AstraZeneca teams have worked so hard to make available to the UK and the world," Pollard said in a statement released by NHS England. "As a pediatrician specialising in infections, I know how important it is that health care workers along with other priority groups are protected as soon as possible -- a crucial role in defeating this terrible disease."

NHS England said the Oxford/AstraZeneca vaccine will be delivered to a small number of U.K. hospitals for the first few days for "surveillance purposes, as is standard practice, before the bulk of supplies are send to hundreds of GP-led services later in the week." Hundreds of new vaccination sites are set to open this week, in addition to the 700 already in operation.

The U.K. became the first country to approve the Oxford/AstraZeneca vaccine for emergency supply last week. Another COVID-19 vaccine developed by U.S. pharmaceutical giant Pfizer and its German partner BioNTech was authorized in the U.K. on Dec. 2 and rollout began a week later. Both vaccines are administered in two doses.

There were 210,479 new cases of COVID-19 confirmed in the United States on Sunday, according to a real-time count kept by Johns Hopkins University.

It's the second straight day that the country has reported more than 200,000 newly confirmed infections. Sunday's tally is less than the all-time high of 297,491 new cases, which the country logged the previous day, Johns Hopkins data shows.

An additional 1,396 deaths from COVID-19 were also registered nationwide on Sunday, down from a peak of 3,750 on Dec. 30, according to Johns Hopkins data.

COVID-19 data may be skewed due to possible lags in reporting over the holidays followed by a potentially very large backlog.

A total of 20,637,537 people in the U.S. have been diagnosed with COVID-19 since the pandemic began, and at least 351,580 of them have died, according to Johns Hopkins data. The cases include people from all 50 U.S. states, Washington, D.C., and other U.S. territories as well as repatriated citizens.

Much of the country was under lockdown by the end of March as the first wave of pandemic hit. By May 20, all U.S. states had begun lifting stay-at-home orders and other restrictions put in place to curb the spread of the novel coronavirus. The day-to-day increase in the country's cases then hovered around 20,000 for a couple of weeks before shooting back up over the summer.

The numbers lingered around 40,000 to 50,000 from mid-August through early October before surging again to record levels, crossing 100,000 for the first time on Nov. 4 and reaching 200,000 for the first time on Nov. 27.