SEOUL, South Korea (AP) - South Korea is tightening recently relaxed restrictions on social gatherings as it grapples with its worst wave of the virus since the start of the pandemic.

Starting next week, private social gatherings of seven or more people will be banned in the densely populated capital Seoul and nearby metropolitan areas, which have been hit hardest by a delta-driven spread that threatens to overwhelm hospital capacities. Gatherings will be limited to eight people in areas outside the capital region, officials said Friday.

Adults will also be required to verify their vaccination status through apps to use restaurants, movie theaters, museums, libraries and other indoor venues. Most of these venues will admit only fully vaccinated adults, while restaurants and coffee shops will be allowed to accept one adult in each group who isn't fully vaccinated or vaccinated at all.

Officials plan to expand the vaccine certificates to children between the ages of 12 and 18 starting in February, when they expect more of them to be vaccinated.

Health Minister Kwon Deok-cheol said the gathering restrictions will be maintained for at least four weeks as officials monitor how the virus situation develops.

Previously, the limit on social gatherings was 10 people in the greater capital area and 12 in other regions, regardless of whether participants were fully vaccinated or not. Kwon said officials also considered limiting indoor dining hours at restaurants, which are currently allowed to open for 24 hours, but decided to hold back for now because of concerns about livelihoods.

“The situation is getting increasingly worse - the daily increase in infections has risen to a level of around 5,000 and there's growing danger that our health care system will hit the limit,” Kwon said during a briefing.

“On top of that, we have confirmed cases of the (new) omicron coronavirus variant and there's concern that it will spread further in local communities,” he added, referring to the country's first six omicron cases found since Wednesday that have been linked to arrivals from Nigeria.

Much remains unknown about the new variant, including whether it is more contagious, as some health authorities suspect, whether it makes people more seriously ill, and whether it can thwart the vaccine.

The Korea Disease Control and Prevention Agency reported 4,944 new cases of the coronavirus on Friday, a day after South Korea set a one-day record of 5,266 new cases. The number of virus patients in serious or critical condition was at a record high of 736. The country's death toll is now 3,739 after reporting 30 to 50 deaths each day in recent weeks.

The virus surge has been a rude awakening for South Korea, which eased social distancing rules at the start of November and fully reopened schools on Nov. 22 in what officials had described as a first step toward restoring pre-pandemic normalcy.

In allowing larger social gatherings and lifting limits on indoor dining hours, officials had hoped that the country's improving vaccination rates would help suppress hospitalizations and deaths even if the virus continues to spread.

However, health workers have been grappling with a rise in serious cases among people in their 60s or older, who have either rejected vaccines or whose immunities have waned after being inoculated early in the vaccine rollout that began in February.

As of Friday, more than 80% of a population of more than 51 million were fully vaccinated. But only 7% of the population have been administered booster shots.