LONDON (AP) — British scientists are warning that the government may need to introduce tougher restrictions to slow the growth of the omicron coronavirus variant. U.K. health officials say omicron is spreading much more quickly than the delta strain and is likely to become the dominant variant in Britain within days. Concern about the new variant led Prime Minister Boris Johnson’s Conservative government this week to reintroduce mask mandates and urge people to work from home. But many scientists say that’s unlikely to be enough. Scientists at the London School of Hygiene and Tropical Medicine said Saturday that omicron could cause between 25,000 and 75,000 deaths in England in the next five months if no other restrictions are put into place.