The leaders of the European Union agreed during a video summit Thursday that borders between the 27 members states should not be closed as part of efforts to contain the COVID-19 pandemic, however, travels should be limited as additional action over mutations of the coronavirus and increasing infections and fatalities throughout the continent.

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.

The tone of urgency was fueled by fears over the spread of highly contagious coronavirus variants that could send already high infection rates skyrocketing and strain hospitals, as is happening in former EU member Britain.

"All non-essential travel should be strongly discouraged both within the country and of course across borders," Ursula von der Leyen, head of the European Commission, told a media conference.

Charles Michel, president of the European Council, said: "It will be probably necessary to take additional restrictive measures in order to limit the non-essential travels and that is the orientation that we are taking."

Both added that further coordination on that issue would be made in "the next days."

But both also said the EU wanted to avoid a repeat of the height of the first wave, in March last year, when several member states panicked and closed off national borders unilaterally, triggering travel and economic chaos.

"It is absolutely important to keep the single market functioning," von der Leyen said, so that workers and freight can continue to cross borders. The EU is "one epidemiological zone," she said.

"We will only contain the virus if we have targeted measures, and not unnecessary measures like a blanket closure of borders, which would severely hurt our economy, but not very much restrict the virus."

But to avoid closing the intra-EU borders in the passport-free Schengen zone, testing needs to be stepped up, leaders agreed.

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 according to remarks carried by the Associated Press (AP).

"Most said free movement must survive but that it is vital to ask not to to travel," Rutte said. "It is essential that we discourage travel in Europe as much as possible. Don't travel, simply don’t travel."

Belgian Prime Minister Alexander De Croo had proposed a temporary ban on nonessential travel during the February school break.

Austrian Chancellor Sebastian Kurz had also voiced support "for stricter entry controls and testing requirements to keep virus mutations out."

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 infection 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.

From Sunday, anybody arriving from outside the EU – possible only for those with essential reasons – could have to have a test for COVID-19 before departure, von der Leyen said.

Within the EU, some countries will apply prior testing for cross-border trips that do not come under essential categories such as workers and truck drivers. From Sunday, France will require a negative Polymerase chain reaction (PCR) test 72 hours before departure for most European arrivals other than those on essential travel, President Emmanuel Macron told the European Council, according to his office.

A statement from Macron's office reported by the Agence France Presse (AFP) said "some of his European counterparts" have also chosen this approach.

Mutations increase worries as death toll rises past 400,000

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 (ECDC) 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," AP reported.

In a study published just before the summit, the ECDC warned of the high dangers of the new variants, like those initiated in Britain, Brazil and South Africa. Ammon said that "member states are also encouraged to accelerate vaccination of high-risk groups, and prepare the health care system for high demand."

Some EU countries have already strengthened restrictions by imposing stricter curfews and more stringent mask requirements on public transport and in shops. Among the measures the ECDC recommends is a ban on nonessential travel and a speeding up of vaccinations.

Currently, the concerning variants remain a tiny proportion of overall cases in most of the EU. But Portugal is serving as an early warning of what may be to come. Its government ordered schools closed for two weeks because of the rapid spread of the British variant, which Prime Minister Antonio Costa said accounted for 20% of infections and could make up 60% as soon as next week.

While there was no indication as yet the new variants were more deadly, there were concerns their faster spread could overload hospital intensive care capacity.

Vaccination, testing to be stepped up

With the health situation at a critical point, the commission also urged member states before the meeting to step up the pace of vaccination, to ensure that at least 80% of those over age 80 are vaccinated by March, and that 70% of the adult population across the bloc is protected by the end of the summer. Michel said there is "a global and clear support for this proposal."

But since the EU doesn't expect vaccines to be ready for mass distribution before April, leaders should in the meantime find efficient ways to contain the new variants. The commission believes that better tracking the virus' mutations with genomic sequencing, coupled with increased use of rapid antigen tests, will be crucial. Those tests, often using saliva samples, are cheaper and faster – though less reliable – than nose-probing PCR tests.

The EU Commission said several EU nations are testing under 1% of samples. It has proposed to "urgently" increase genome sequencing to at least 5% of positive test results and would ideally see that figure reach 10% to detect the variants. Member states unanimously agreed Thursday on a common framework for the use of rapid antigen tests and the mutual recognition of PCR test results across the bloc of 450 million inhabitants.

Discussions also focused on the disruption of vaccine deliveries after Pfizer last week announced a temporary reduction that has affected all EU countries. The EU has sealed six vaccine contracts for more than 2 billion doses, but only the Pfizer-BioNTech and Moderna vaccines have been approved for use so far.

The EU now expects Pfizer to keep the drop in deliveries limited to this week, while resuming full distribution again next week, with the resulting backlog made up during February.

Leaders also weighed a Greek proposal to issue vaccination certificates to ease travel. But with doubts about whether the people vaccinated could still be contagious, and only a small fraction of the EU population already vaccinated, they agreed it was too soon to decide if vaccination proof certificates should be considered as travel documents.