London and surrounding areas will be placed under the UK's highest level of coronavirus restrictions later this week, Britain's Health Secretary Matt Hancock has announced.

The tougher measures will be introduced in a bid to curb "very sharp, exponential rises" in daily cases and hospital admissions, Hancock said on Monday.

Scientists have identified a "new variant" of the virus in the south of England that may be causing infections to spread faster, the minister explained.

On Friday, the "R number" — indicating how many other people someone with the virus will infect — was between 0.9 and 1.1 for London, according to the government's website.

More than 201,000 cases have been registered in the capital — home to around 9 million inhabitants — and more than 7,000 people have died in hospital.

What is the new coronavirus variant?

"We are aware of this genetic variant reported in 1,000 individuals in England," the WHO's top emergencies expert Mike Ryan told a news briefing in Geneva.

"Authorities are looking at its significance. We have seen many variants, this virus evolves and changes over time," added Ryan.

"There's currently nothing to suggest it is more likely to cause serious cases and the latest clinical advice is it is highly unlikely to fail to respond to a vaccine," said Hancock.

What new measure will London face?

The British capital as well as parts of the bordering counties Essex, Kent and Hertfordshire move into a "Tier 3" restrictions category from 00:01 a.m. local time (00:01 UTC) Wednesday.

Theaters, pubs, restaurants and other hospitality venues will have to close, except for takeaway food.

People will be banned from socializing with anyone outside of their household. Londoners will still be able to meet in groups of up to six in public places outside.

Shops, hairdressers and schools will be allowed to stay open.

"I know this is difficult news, but this action is absolutely essential to help prevent more damaging and longer-lasting problems later," said Hancock.

London Mayor Sadiq Khan called the rise in cases "deeply concerning." But he warned the move would be "catastrophic" for pubs, bars and arts venues.

The United Kingdom has the seventh-highest total caseload worldwide with over 1.8 million cases. It became the first country to begin rolling out the widely-tested and independently-reviewed BioNTech-Pfizer COVID-19 vaccine last week.

kmm/rc (AFP, AP, Reuters)