As Europe struggles amid increasing COVID-19 cases with the emergence of the new variant, omicron, the European Council did not rule out new travel restrictions.

Official conclusions adopted by the EU leaders said "continued coordinated efforts" are needed to respond to COVID-19 developments and that any restrictions adopted should not "disproportionately hamper free movement" within or into the bloc.

The discovery of the omicron variant has prompted the return of COVID-19 testing for arrivals in Ireland, Greece and Italy – even for vaccinated travelers – raising eyebrows among some EU leaders.

Divisions were apparent before the start of the summit with some leaders advocating against further travel restrictions.

Luxembourg Prime Minister Xavier Bettel said new travel restrictions were not a solution. He also said the mental health of the public also needs to be considered.

Booster shots should be prioritized, Belgian Prime Minister Alexander de Croo said.

Greek Prime Minister Kyriakos Mitsotakis defended the return of testing however as a means to reduce infections during the festive period and buy time for his government's booster shot campaign.

The European Union is attempting to maintain a common approach in the pandemic as new COVID-19 developments occur.

Despite differences on travel restrictions, the bloc's leaders agreed in their official conclusions on the importance of a coordinated approach for the validity period of the EU's digital COVID-19 certificate.

The digital pass permits the holder to travel in the EU if they are vaccinated, recovered from COVID-19 or have recently tested negative for the virus. It was central to the coordinated return of freedom of movement in the EU after pandemic lockdowns.

Some EU member states are urging for the COVID-19 certificate to be adapted to show the up-to-date validity of the holder's vaccination status.

It comes as vaccine booster campaigns continue across the bloc risking disparity in the EU between different member states' validity periods.

Some EU governments have changed the criteria for full vaccination status as well, to include a third vaccine dose in some cases.

Meanwhile despite ongoing debates in some EU member states surrounding mandatory vaccinations, the topic "was not at the heart" of the EU leader's discussion on omicron, an EU official said.