Hospitals in the United Kingdom's capital are struggling because of the fast-spreading Omicron variant of the novel coronavirus.

London, with a population of around 10 million, has significantly more infections and a much higher percentage of infections than anywhere else in the UK and has been described as the nation's Omicron "epicenter".

The virus, which causes COVID-19, is creating problems by not only hospitalizing more people but also making more National Health Service, or NHS, employees take sick leave. With more work to do and fewer people to do it, hospitals are already dealing with massive problems.

The Financial Times newspaper said 220 people with COVID-19 were admitted to London hospitals on Friday, which was the most pandemic-related admissions in a single day since Feb 10.

At the same time, The Health Service Journal said the number of London NHS workers off sick because of COVID-19 doubled in a four-day period last week. The journal said one NHS worker in three will be off work by Dec 31 if the trend continues.

One unnamed official told the journal: "Some NHS workplaces have been decimated."

Danny Mortimer, chief executive of NHS Employers, told the Financial Times the situation was "extremely concerning".

Mortimer said NHS workers on sick leave typically account for around 5 to 6 percent of the workforce at this time of year, but that percentage is already up to 8 or 9 in some places.

"Lots and lots of our colleagues are changing their plans over the next week, so that they can work extra shifts," he said, while acknowledging some non-emergency procedures will surely have to be canceled.

Mortimer said sickness among NHS workers is also putting pressure on care homes, neighborhood medical clinics, and on community services, where medics visit people in their homes.

"The whole system is under pressure," he said.

Chris Hopson, chief executive of NHS Providers, tweeted on Saturday that the pressure was so intense in the capital that "trusts (are) now having to postpone nonessential activity".

The BBC said London's emergency services-its paramedics, law enforcement officers, and firefighters-are also reporting large numbers of people off sick because of COVID-19. So far, the services are continuing to operate normally, the broadcaster added.

London's mayor, Sadiq Khan, declared a "major incident" in the capital on Saturday because of the rapid spread of the Omicron variant.

The declaration means emergency services, the NHS, and local governments must now adopt special plans, and will also not be forced to guarantee their normal service levels.

The Fire Brigades Union said last week almost one third of its trucks were out of action because of worker absences but that it was still meeting its targets.

And a London Ambulance Service spokesperson told the Evening Standard newspaper it was managing to meet its responsibilities, despite huge numbers of workers on sick leave because of COVID-19.

"We have increased access to testing for staff, which allows those who test negative to return to work quickly and safely," he said.