After a discussion with von der Leyen on coronavirus situation, Slovenian Prime Minister Janez Jansa welcomed the EU proposal on the bloc's external border. "Finally good news from Brussels," he wrote on Twitter.

Even more countries still remained their internal border open, states of emergency or extraordinary have been declared by some to tackle the disease. Others are preparing for similar policies.

As European countries are grappling with the epidemic, WHO Director-General Tedros Adhanom Ghebreyesus warned on Monday that the escalation in testing, isolation and contact tracing is not urgent enough. These measures are the backbone of the COVID-19 response, said Tedros.

According to the WHO chief, the most effective way to prevent infections and save lives is breaking the chains of COVID-19 transmission.

"You cannot fight a fire blindfolded and we cannot stop this pandemic if we don't know who is infected," he said, calling for every suspected case testing.

"We have a simple message for all countries: test, test, test. Test every suspected #COVID19 case," the WHO said in tweet.

Some European countries, such as France, have admitted the possible underestimate of the epidemic.

France has confirmed 6,633 coronavirus infection cases and 148 deaths by Monday evening. These figures represent 1,210 new cases of infection and 21 additional deaths in one day.

However, these data "underestimate the real number" due to the difficulty of identification and biological confirmation of all COVID-19 cases and the fact that only part of the sick is now tested, said the country's Health Ministry.

To test more suspected cases, Lithuanian Ministry of Health decided to open drive-through COVID-19 mobile testing points in its 10 municipalities starting on Monday.

And turning a park in Dublin into a drive-through testing center is also under discussion, according to Irish national radio and television broadcaster RTE on Monday.

Europe, as whole, is facing a tough mission to bring the virus under control, as among some 83,000 confirmed COVID-19 cases outside China as of Monday morning, around 56,000 are in Europe.