LONDON—Officials moved to reimpose tougher measures in various European nations, citing a new wave of COVID-19 infections spurred by the Omicron variant, with the Netherlands imposing a nationwide lockdown. All non-essential stores, bars and restaurants in the Netherlands will be closed until Jan. 14 starting Sunday, caretaker Prime Minister Mark Rutte said at a hastily arranged press conference Saturday night. Schools and universities will shut until Jan. 9, he said. Residents only will be permitted two visitors except for Christmas and New Year’s, when four will be allowed, according to Rutte. “The Netherlands is going into lockdown again from tomorrow,” he said, adding that the move was “unavoidable because of the fifth wave caused by the omicron variant that is bearing down on us.” Shoppers fearing the worst swarmed to commercial areas of Dutch cities earlier Saturday, thinking it might be their last chance to buy Christmas gifts. Rotterdam municipality …