Uefa has "decisions to make" if Scotland cannot guarantee having fans at Euro 2020 games at Hampden, says Scottish FA boss Ian executive Maxwell.
But he said there is "no sign" yet of games being stripped from Glasgow.
First Minister Nicola Sturgeon said on Friday that Scotland is "absolutely intent" on hosting matches this summer.
That came amid concerns that a failure to say by 7 April how many fans will be allowed could result in Glasgow being removed as one of 12 host cities.
"We're working as hard as we can to get there," chief executive Maxwell told Sportsound on Saturday. "We're not at the point where there's any signs that the games will not be at Hampden.
"If we can't provide what Uefa require - the same as Wembley, the same as Baku, or Bilbao, or any of the other stadiums - then Uefa have got decisions to make."
Ms Sturgeon said on Friday that "all countries are grappling with this, not just Scotland".
She added: "We are standing here on 5 March and, while we are really hopeful and you are getting signs of a lot of optimism from us today, looking too far ahead is just difficult to do."
Maxwell confirmed that Uefa wants at least 20-30% of the stadium capacity filled by spectators and that the Glasgow organisers are "working on that as a minimum and trying to increase that".
"It seems feasible," he told BBC Radio Scotland. "At the moment, we have a spectator cap of 300 in a level one area, and no-one can be under any illusions that is going to have to change, but there has been a lot of improvements.
"We need to learn from other events across Europe and ensure we can get the number as high as it possible can be while doing it in the safest possible way."
On Friday, the Football Association told the BBC it would host more Euro matches if asked to do so by Uefa. Wembley is currently due to host seven games.
"We would be delighted to help, as would a number of other countries I'm sure, but that's not our understanding of the situation at the moment," said chief executive Mark Bullingham.
Scotland's men will this summer play at their first major tournament for 23 years in the Euro finals, which were postponed by 12 months because of the coronavirus pandemic.
With two of Scotland's three group matches scheduled to take place at Hampden, starting with the Czech Republic on 14 June, Ms Sturgeon said that makes the Scottish government "particularly keen" to host games.
While other host countries are also yet to formally say whether they will allow fans, some have given an indication of their intention to do so.
"While nothing in a global pandemic can be certain, I very much want and hope over the next few weeks [we] get a greater degree of confidence in saying we expect to be one of the many Tartan Army fans cheering on Scotland at Hampden later in the year," said Sturgeon.
Bullingham said he thought international fans may be allowed into the semi-finals and final at Wembley, with the earlier stages of the tournament restricted to domestic fans.
'A lot of be considered'
Scotland's national clinical director Jason Leitch on Off The Ball
There's a lot of hope that we will get there by June but, to balance that, in the whole of Europe over the last seven days there were a million new infections.
Half of Europe still has an accelerating pandemic, and half - fortunately including Scotland and the UK - has a decelerating pandemic.
We're still desperate to host the Euros. Everything we can do to get to there we will do. That doesn't just rely on the government making a decision, though. It depends on all of us getting the incidents down and that's on every single one of us.
We'll need to think about Scottish supporters being transported in and our of the country [should Hampden not be hosting].
We also need to think about what we're going to do with Czech Republic supporters, with Croatia supporters. So there's a lot to be considered before you can just say "Yes, let's do it".