Amsterdam has committed to allowing fans to attend Euro 2020 games in June ahead of UEFA's deadline for host cities to submit their plans on Wednesday, while the Spanish football federation has ruled that Bilbao will be unable to host tournament games.
European football's governing body has asked all 12 host cities to come up with their plans for fan capacity at venues for the tournament which kicks off on June 11.
UEFA president Aleksander Ceferin has said that all host cities must guarantee some fan presence, saying they will not play games behind closed doors, although the pandemic has made it tough for organisers to give definitive commitments.
A final decision on the venues is expected at UEFA's congress on April 20.
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Euro 2020 was postponed by a year due to the Covid-19 pandemic and most of Europe's football has taken place without fans for the past year.
The Royal Netherlands Football Association (KNVB) said "at least 12,000 spectators" will be able to attend matches at the Johan Cruyff Arena in Amsterdam.
"Depending on developments surrounding the COVID-19 pandemic in June, there is a chance that more fans will be allowed inside the stadium. This ambition has been expressed jointly by the Royal Netherlands Football Association (KNVB), the Dutch cabinet and the Amsterdam city council," the KNVB said in a statement.
The exact amount of fans allowed in will be determined at a later stage by the Dutch government, which on Wednesday warned that a large COVID-19 outbreak in the weeks before the tournament could still mean that the audience would be reduced.
All spectators will need to test negative for Covid-19 shortly before the game, and will have to adhere to a strict safety protocol inside the stadium.
Meanwhile, the Spanish football federation has declared Bilbao will be unable to hold Euro 2020 matches with spectators, endangering the city's chances of remaining as a host for the rescheduled tournament.
Bilbao's city hall had told UEFA it is ready to stage Euro 2020 games at the San Mames stadium at 25 per cent capacity if coronavirus infection rates drop below current levels.
But the federation said in its own statement that the Basque government's conditions were "impossible to meet" in time for the start of the tournament on June 11.
Spain are due to play all three of their group stage matches at the 53,000-capacity San Mames, which is also set to host a last-16 match.
The Romanian Ministry of Youth and Sport announced that up to 13,000 spectators will be able to attend matches set to take place at the Arena Nationala in Bucharest.
Dublin appears the most at risk of not being able to offer a guarantee of fan presence at games, with Prime Minister Micheal Martin saying it would be "very challenging".
On Tuesday, the Italian federation (FIGC) said their government would "identify the best solutions" to allow fans to be at Rome's Olympic Stadium although it said a government committee would make an evaluation of the pandemic situation and "examine the possibility of providing a limited presence of the public".
Sturgeon hopes fans will be at Hampden for Euro 2020
Scotland's First Minister Nicola Sturgeon has told Sky Sports News she is "hopeful" fans will attend Euro 2020 matches at Hampden Park.
Speaking at her daily press briefing on Tuesday, Sturgeon said she was "desperate" for the matches to take place in Scotland and said "I think we will see some kind of vaccine certification starting to be used".
When questioned by Sky Sports News about the fan experience supporters can expect, Sturgeon answered: "We have a deadline to make a proposal to UEFA tomorrow. I'm not going to get into that just now, it is important we have a proper discussion within the proper processes that have been set there.
"I have said this before and I know I am not alone here, there are many people who will feel it even more strongly than I do - I desperately want to have these matches played here in Scotland, at Hampden.
"Not least because we will have the ability to cheer on Scotland in a couple of those matches. It is really important for sporting fans but also just the idea that that will be possible come June gives us all a lift and belief that things are getting back to normal.
"The whole issue of vaccine passport certification, I think we have gone into some of the issues with that earlier on. I think we will see some kind of vaccine certification starting to be used, other organisations will ask for it.
"We have some issues to think through in order to give assurance to the public. In terms of the European Championships, there are other countries involved in this and some of those countries have real challenges on their hands with Covid right now so there are tough issues for all of us to grapple with.
"I can't stand here in early April and give absolute 100 per cent guarantees for June on anything - that is not the nature of what we are dealing with but I am very, very hopeful.
"I'm hopeful that I might be at Hampden to cheer on Scotland at the European Championships and we will continue to work as hard as we can to make that happen."