STOCKHOLM (Reuters) - Sweden will require visitors from other Nordic nations to have a vaccine pass to cross the border as it gradually tightens restrictions amid rising cases of the Omicron variant of the coronavirus, the government said on Thursday.

       "We see an increase in infections in Europe, but also in our neighbours," news agency TT quoted Prime Minister Magdalena Andersson as saying.

       "For visitors from any country except the Nordics, we have a requirement for a COVID pass. Today, the government is going to take the decision that there will be the same requirement also for the Nordic countries."

       The new regulation will come into force on December 21, TT said.

       Sweden has seen a sharp rise in new infections in recent days, if from a low level. It has reintroduced a limited number of measures and has said further steps would be needed if infections kept on climbing.

       Authorities will hold a news conference at 0900 GMT.

       Earlier this week, Norway tightened COVID restrictions in a bid to limit the spread of the Omicron variant amid record levels of infections and hospitalizations.

       Denmark has also reintroduced restrictions, including closing primary schools and limiting opening hours for restaurants and bars.

       (Reporting by Simon Johnson; editing by Niklas Pollard)