Eight of 12 host cities have guaranteed the return of supporters to grounds for Euro 2020 but UEFA confirmed that the host-status of the remaining four cities – Munich, Rome, Bilbao and Dublin – is in doubt after their national associations failed to offer assurances over fans.
The Football Association (FA) has guaranteed that Wembley will be 25 per cent full – a crowd of 22,500 – for England's three group matches and one last-16 tie, and are aiming to confirm a higher capacity, thought to be at least 50 per cent, for the semi-finals and final at the national stadium by early June.
The Hungarian authorities are aiming to host 68,000 fans at full-capacity for the four matches at the Puskas Arena in Budapest, while Amsterdam, Bucharest, Copenhagen and Glasgow have confirmed a capacity of 25 to 33 per cent.
St. Petersburg and Baku have confirmed capacities of 50 per cent.
Amsterdam, Bucharest, Copenhagen and St. Petersburg could all increase their capacities by the end of April, depending on conditions with the virus in their countries.
Munich, Rome, Bilbao and Dublin were unable to offer any assurances over fans attending games, however, and could yet be removed as hosts, with England strongly tipped to be handed extra matches in the event.
In a statement, UEFA said: "The remaining four cities have until 19 April to provide additional information on their plans and final decisions will be made on that date regarding the staging of matches in those four venues."
UEFA also warned supporters they would find travelling for the tournament "challenging due to ever-changing restrictions", highlighting factors such as national quarantine.
However, the governing body confirmed that Baku, Budapest and St. Petersburg were all planning exemptions from entry restrictions to ticket-holders.
Wales fans travelling to Baku for their three group matches will be exempted from quarantine if they can show proof of a recent negative Covid-19 test.
"Fans wishing to travel to the host countries to watch the matches will find it challenging due to ever-changing restrictions," read UEFA's statement.
"They will have to comply with the border entry restrictions and requirements (including quarantine) in force at the time, as no exemptions will be granted for ticket-holders for nine host countries.
“Only three host countries are planning exemptions from entry restrictions and requirements. Ticket holders travelling to Baku, Budapest and St. Petersburg may be able to benefit from special procedures that will exempt them from entry bans or quarantine requirements.”
Fans travelling to St. Petersburg will also have to show proof of a negative Covid test, while supporters entering Hungary will have to show proof of two negative tests within the previous five days or a certificate of immunity.