The European Union — and Greece by extension — extended its ban on entry of non-EU citizens until July 31, when lists will once again be revisited.

The announcement also imposed restrictions on Serbia and Montenegro, which were originally in the “safe list” when the EU opened its borders on July 1.

Twelve non-EU countries remain on the list of “safe countries” and are exempted from the travel ban. They are: Algeria, Australia, Canada, Georgia, Japan, Morocco, New Zealand, Rwanda, South Korea, Thailand, Tunisia and Uruguay.

U.S. nationals remain banned from entry into Greece, with the exception of those holding Greek nationality.

The restrictions have forced most airlines operating routes between North American destinations and Athens to cancel all or most of their summer non-stop flights.

American, Delta, Emirates and United Airlines all cancelled their summer 2020 flights from various American gateway cities.

Since Canada was placed on the “safe country” list on July 1, Canadian carriers Air Canada and Air Transat have resumed operations with non-stop flights between Toronto and Montreal with Athens.