ATHENS — Greece may be a “pillar of stability in the region,” as the United States often says, but the State Department told Americans it's not safe to go there yet  because of COVID-19 despite the country welcoming them.

The US State Department issued a Travel Advisory Level 4 for Greece because of the still lingering pandemic, said Kathimerini, despite an accelerating vaccination program driven by the New Democracy government after a slow start.

The same advisory has been given about nearly 100 countries but the European Union said Americans who have been vaccinated should be able to travel to Europe by summer, easing existing travel restrictions, said Reuters.

European Commission President Ursula von der Leyen told The New York Times that the union’s 27 members would accept, unconditionally, all those who are vaccinated with vaccines that are approved” by the European Medicines Agency. The agency has approved the three vaccines used in the United States, Pfizer-BioNTech, Moderna, and Johnson & Johnson (J & J) as well as the United Kingdom's AstraZeneca.

“The Americans, as far as I can see, use European Medicines Agency-approved vaccines,” von der Leyen said. “This will enable free movement and travel to the European Union,” but she didn't say when travel could begin again.

Adopting an idea from Greek Prime Minister Kyriakos Mitsotakis, the EU agreed to begin using COVID-19 travel certificates for people who've been vaccinated, have recovered from the Coronavirus or tested negative.

The third wave of the pandemic has led the US authorities to upgrade their advisory on Greece from Level 3 to 4 and the other countries on advice of the US Centers for Disease Control and Prevention (CDC).

A State Department spokesperson told Greece's state broadcaster ERT that Greece isn't being singled out but the advice against Americans going there comes as the doors are being opened to them, if they're COVID-19 free.

Americans were locked out of Greece when the pandemic was raging in 2020 and are a key market – especially Greek-Americans – as US tourists spend nearly 1 billion euros ($1.21 billion) annually in the country.

Despite the warning, major US air carriers, including Delta, United and American are offering non-stop service to Athens as those who fly with a stop in an EU country that doesn't allow Americans could find themselves thwarted during their trip.