Britain's Health Secretary Sajid Javid declined on Sunday to rule out the chance of further Covid-19 restrictions before Christmas because of the “fast moving” situation. The UK recorded a surge in cases of the Omicron coronavirus variant on Saturday, which government advisers said could be just the tip of the iceberg. London's mayor declared a “major incident” to help the city's hospitals cope. Asked whether he could rule out restrictions before Christmas, Mr Javid told the BBC: “We are assessing the situation, it is very fast moving.” “There are no guarantees in this pandemic I don't think. At this point, we just have to keep everything under review.” Mr Javid said the government was taking the “sobering” advice of its scientists seriously, watching the data on an “almost hourly basis”, and would balance that against the broader impact of restrictions on things such as businesses and education. He said there was a still a lot that is not known about Omicron, but waiting until data is clearer may leave it too late to react to it. Prime Minister Boris Johnson last week reinstated rules requiring face masks in shops and ordered people to show proof of vaccination or a negative coronavirus test before entering night clubs and other crowded venues. More than 100 of his own Conservative MPs voted against the measures. Government scientific advisers have recommended more far-reaching restrictions to prevent hospitals from being overwhelmed, according to leaked minutes from a meeting. Asked if Mr Johnson was too weak to bring in further restrictions, Mr Javid said: “No, I don't think that's the case … if the government felt that further action had to be taken of course we would present that to parliament and it would be for parliament to decide.” The number of Omicron cases recorded across the country hit almost 25,000 on Friday, up by more than 10,000 cases from 24 hours earlier, the UK Health Security Agency said. Mr Javid said the government believed around 60 per cent of new Covid-19 cases in England were now Omicron. Nations across Europe are moving to reimpose tougher measures to stem a new wave of Covid-19 infections spurred by the highly transmissible variant. The Dutch government imposed a tough nationwide lockdown starting Sunday in an attempt to rein in sharply rising levels of infections, and ministers in France, Germany, Austria and Cyprus have tightened travel restrictions.