With numbers of coronavirus cases in the U.K. exploding — driven by the highly transmissible omicron variant — the government is leaving open the possibility of soon imposing another round of restrictions, the country’s health secretary said Sunday.

Scientific advisers have warned lawmakers that more action is needed because the surge is threatening to overwhelm the U.K.’s health system, even after the government announced a long-resisted coronavirus contingency plan, earlier this month, urging people to work from home if possible and extending a face-mask mandate.

Over the weekend, Sadiq Khan, London’s mayor, declared a "major incident” — an emergency status that frees up resources — in the capital, and there has been speculation on the possibility of a short-term nationwide lockdown.