The Europa League has been left in limbo as a result of the coronavirus outbreak with two ties involving Italian clubs called off and four more games scheduled for Thursday to be played behind closed doors.
UEFA on Wednesday confirmed that the last 16, first legs between Inter Milan and Getafe in Italy, and between Sevilla and Roma in Spain, would not go ahead as planned.
The announcement came after Spanish authorities suspended flights until March 25 to the country from Italy, which has been the worst hit European nation by an outbreak now classified as a pandemic by the World Health Organization.
With the second legs due to be played next week, it is unclear how the ties will be resolved.
"There is the possibility that the tie will be played as a one-off match on a neutral ground," said the Getafe Director General, Clemente Villaverde. "In any case we will accept whatever decision is taken by UEFA."
The Spanish side had declared on Tuesday night that they would refuse to travel for the tie. All domestic sports events in Italy have been suspended until 3 April, but European competitions are under the jurisdiction of UEFA so can in theory still go ahead.
Meanwhile Eintracht Frankfurt confirmed on Tuesday that their game at home to Swiss side Basel would go ahead behind closed doors due to the extent of the outbreak in Germany's financial capital.
Uncertainty continues to surround the second leg in Switzerland next week, however. Basel have said the game will not go ahead in the country, where all football in the top two domestic leagues has already been postponed for the rest of the month.
Wolfsburg's game against Shakhtar Donetsk will be played behind closed doors, as will the match between Olympiakos and Wolverhampton Wanderers in Greece.
On Tuesday it was announced that Olympiakos owner Vangelis Marinakis - also the owner of English club Nottingham Forest - had tested positive for coronavirus. He said he was taking "all necessary measures" and "feeling well".
Wolves asked that the match be postponed, but said on Tuesday night that UEFA had rejected that request.
"Our position is that the trip poses unnecessary risks to our players, staff, supporters and the families of all who travel, at such critical and uncertain times," Wolves said.
Meanwhile, Manchester United's game away to LASK Linz in Austria will also be played behind closed doors in line with the guidance of the Austrian government.
The news will be a disappointment to supporters of the Austrian club hoping to see their team spring a surprise.
United's 2-0 derby win over Manchester City on Sunday saw them extend their current unbeaten run to 10 games, with eight clean sheets in that time.
Coached by the French former Bayern Munich and Crystal Palace defender Valerien Ismael, LASK are six points ahead of Salzburg at the top of the Austrian Bundesliga as they chase a first league title since 1965.
They lost to Club Brugge in Champions League qualifying this season. The Belgians then lost to Ole Gunnar Solskjaer's side in the last round of the Europa League.
That leaves just two matches set to take place before a crowd: Istanbul Basaksehir against FC Copenhagen in Turkey, and Rangers against Bayer Leverkusen at Ibrox.
Leverkusen have already announced that the return leg next week "was set to be played behind closed doors" after health officials in the German state of North Rhine-Westphalia called for events bringing together more than 1,000 people to be postponed.