European Union leaders agreed that borders should remain open and assessed more measures to counter the spread of coronavirus variants during a video summit Thursday as the bloc’s top disease control official said urgent action was needed to stave off a new wave of hospitalizations and deaths.

Expressing great concern about the virus’ mutations, the 27 leaders looked at further border restrictions like limits on all non-essential travel, better tracking of mutations and improving coordination of lockdowns.

Though worried that another surge of deaths across the EU was imminent, they could not immediately agree on whether or not to halt non-essential travel.

“It is of great importance not to travel, but you cannot immediately enforce this legally,” Dutch Prime Minister Mark Rutte said after the conference call.

European Commission president Ursula von der Leyen insisted on the importance of keeping borders open to ensure that goods continue to move smoothly while introducing measures “that keep us all safe.”

She said leaders discussed a proposal to introduce new trans-border “dark red zones” where infections rates are particularly high and where all non-essential travel should be discouraged. Travelers from these areas could be required to undergo tests before their departure and be placed in isolation upon arrival in another location. Von der Leyen said the commission will make precise recommendations to member states in the coming days.

Some 400,000 EU citizens have died from COVID-19-related causes since the start of the pandemic, and the head of the European Centre for Disease Prevention and Control, Andrea Ammon, said that “an increasing number of infections will lead to higher hospitalization and death rates across all age groups, particularly for those in older age groups.”