The new potentially more contagious Omicron variant of the coronavirus popped up in more European countries on Saturday, just days after being identified in South Africa, leaving governments around the world scrambling to stop the spread, AP reports.

The UK on Saturday tightened its rules on mask-wearing and on testing of international arrivals after finding two cases. New cases were confirmed on Saturday in Germany and Italy, with Belgium, Israel and Hong Kong also reporting that the variant has been found in travellers.

In the US, Dr Anthony Fauci, the government top infectious diseases expert, said he would not be surprised if the omicron variant was already in the United States, too.

A number of pharmaceutical firms, including AstraZeneca, Moderna, Novavax and Pfizer, said they have plans in place to adapt their vaccines in light of the emergence of omicron. Pfizer and its partner BioNTech said they expect to be able to tweak their vaccine in around 100 days.