US tourists vaccinated against COVID-19 will be able to visit the European Union in the coming months, European Commission chief Ursula von der Leyen said in an interview on Sunday with The New York Times.

Signaling a major change in EU policy as vaccinations step up worldwide, von der Leyen gave no timetable, but the Times said that the new rules could be in place by this summer.

"The Americans, as far as I can see, use European Medicines Agency-approved vaccines," she said. "This will enable free movement and the travel to the European Union.

"Because one thing is clear: All 27 member states will accept, unconditionally, all those who are vaccinated with vaccines that are approved by EMA."

The EMA, the bloc's drug regulator, has approved the three vaccines being used in the United States -- Moderna, Pfizer and Johnson & Johnson.

The Times said the US's rapid vaccination program, and progress in talks over how to use vaccine certificates, were behind the plan to allow the return of leisure travel from the US to EU.

Von der Leyen said that the United States was making "huge progress" and noted it was on track to vaccinate 70 percent of adults by the middle of June.

Resumption of travel would depend "on the epidemiological situation, but the situation is improving in the United States, as it is, hopefully, also improving in the European Union," she added.

The pandemic has ravaged tourism on the continent, with many nations shutting borders for non-essential travel.

Greece said last week that travelers from the EU and five other countries who are vaccinated or have a recent negative Covid test will no longer have to quarantine on arrival.

The country is eager to reopen its badly hit tourism sector and has ramped up its vaccine rollout in the hopes of building up immunity among residents.

The European Union has said it wants to launch a vaccine passport for travellers, though plans have not yet been formalized.