European Championship organisers received assurances from Spain, Scotland and the Netherlands on Wednesday about plans to allow fans into stadiums in June as coronavirus restrictions are eased.
Irish authorities, though, remain unable to offer the same guarantees to UEFA about the return of spectators, leaving Dublin at risk of being cut from the 12-city tournament hosting across Europe.
England is one of the countries being considered to relocate the four matches that were due to be staged in in Dublin. But with Wembley already the location for seven games across a month, including the semifinals and final, another stadium in the country would be required.
Group E's fixtures are split between Dublin and Bilbao and Spain had also been at risk of losing games. But authorities in Bilbao have now told UEFA that it will guarantee the 53,000-capacity San Mamés can have up to a quarter of seats filled.
A similar number of fans should be at games in Amsterdam, with the Dutch football federation saying authorities want to allow at least 12,000 spectators who have presented a negative COVID-19 test result into the Johan Cruyff Arena.
And the Scottish government determined on Wednesday that up to 12,000 fans could be allowed into Glasgow's four games, with Hampden Park at 25% of capacity.
Bilbao, Glasgow and Amsterdam have three games in the group stage and a round of 16 matches. Authorities in the Netherlands warn that if the coronavirus situation deteriorates, then the presence of fans in the Amsterdam stadium will have to be re-evaluated.
"We look forward to welcoming 12,000 spectators to the Johan Cruyff Arena, but we are aware that the coronavirus is unpredictable and there are no guarantees," said Gijs de Jong, a tournament director in Amsterdam. "However, we remain hopeful that, come June, the situation will have improved to the point where we can allow even more spectators to attend."
The rescheduled European Championship is due to open on June 11 in Rome after Italy said Tuesday that it is ready to let fans back into stadiums by then.
Fans have been banned from matches in Italy for the majority of the past year, apart from a brief period shortly after the start of the season when up to 1,000 spectators were allowed into games.
The city of Munich was less committal in its statement on Tuesday, saying it is "conceivable and desirable that spectators can be in the stadium" for its four games, including a quarterfinal.
The Football Association of Ireland said it was not able yet to provide assurances on minimum fan numbers as required by competition organizers.
"We have made our submission to UEFA today and now await their response once submissions from all 12 host cities have been received and considered," FAI Chief Executive Jonathan Hill said.
The city with the most games is London, which will stage seven fixtures at Wembley including the semifinals and final. Authorities hope the 90,000-capacity might even be full by the end of the tournament.
Russia has already confirmed that St. Petersburg's 65,000-seat stadium will be filled to at least 50% capacity for its four games. Denmark is planning on up to 12,000 fans being allowed into the four matches at the 38,000-capacity Parken Stadium. A similar number could be attending games in Romania under government plans for the 55,000-capacity national stadium in Bucharest to be at least a quarter filled.
Baku, Azerbaijan and Budapest, Hungary are also due to be part of the hosting of the tournament that has been rearranged for 2020.
