Manchester United's Champions League match against Young Boys next week may have to be switched to a neutral venue.
Switzerland imposed new restrictions on UK arrivals on Saturday night in response to the emergence of the Omicron variant of Covid-19, meaning anyone coming from the UK would need to provide a negative Covid test and quarantine for 10 days, regardless of vaccination status.
The PA news agency reports that UEFA is trying to establish whether the Young Boys travelling party would be exempt from the regulations upon their return from Manchester.
If not, Annex J of UEFA's Champions League regulations state that the onus is on the home club to propose an alternative venue.
"If restrictions imposed by the national/local authorities of the visiting club's country apply to the visiting club's travel to play the match or its return home after the match, the home club must propose a suitable alternative venue....which may be in a neutral country (within the territory of a UEFA member association) that would allow the match to take place and would not cause the visiting club any restrictions in either travel direction," the regulations state.
"If the home club fails to propose such suitable alternative venue within the aforementioned deadline, the UEFA administration will take a final decision on the match venue and/or match date.
"The home club will remain responsible for the organisation of the match and both clubs will share the related costs in equal measure."
The regulations surrounding the completion of the group phase state: "In any case, the UEFA administration may reschedule matches if this ensures a match is played and allows the group stage to be completed accordingly.
"This should not jeopardise the schedule of any forthcoming matches in the competition or other UEFA competitions. Such decisions of the UEFA administration are final.
"All group stage matches must be finished by 31 December, 2021."
United's place in the last 16 was secured with victory over Villarreal in their last group match on 23 November.