Officials in Brussels confirmed the European Union was in discussions with the United States to allow tourists who have had both doses of approved vaccines to visit Europe under an agreed system of open travel.

The EU has said previously it is likely to welcome tourists from the US this summer as vaccination programs accelerate and existing travel restrictions are eased.

Speaking to The New York Times, European Commission President Ursula von der Leyen said the union's 27 members would accept all US citizens inoculated with vaccines approved by the European Medicines Agency.

These would include the three vaccines that have been authorized for use in the US-Moderna, Johnson & Johnson and Pfizer-BioNTech.

The move is part of wider EU efforts to coordinate travel inside the bloc and from non-EU countries to encourage summer tourism.

"The Americans, as far as I can see, use European Medicines Agency-approved vaccines," von der Leyen said in an interview on Sunday. "This will enable free movement and travel to the European Union."

Von der Leyen did not give a specific timeline, and individual EU member states are permitted to enforce stricter rules than the bloc as a whole, noted Euronews.

A spokesperson for the EU would not confirm whether an agreement with the US would require reciprocal travel rights to inoculated Europeans, said the Financial Times. The paper added one complicating issue is that millions of European residents have received the Oxford-AstraZeneca vaccine, which the US has not yet approved.

Any deal agreed would increase pressure on the EU from countries that have falling infection rates, the FT said, noting the EU has not started talks with the UK, "which accounted for about 75 million visits to the EU in 2019, compared with just under 40 million from the US".

Reuters news agency noted EU countries will soon begin negotiations on so-called green pass certificates, or COVID-19 travel passes, that will allow citizens of member states to travel within the union if they have been vaccinated against the disease, recovered from an infection, or have tested negative.

On Monday, Greece ended quarantine measures for travelers from a number of countries, including the US and the United Kingdom. The United Arab Emirates and Israel have also done the same, said Euronews.