Manchester City will have to play Real Madrid in Portugal for the second leg of their Champions League last-16 tie if they are unable to host the game at the Etihad Stadium, UEFA has confirmed.
A decision on the venues involving all British clubs remaining in European competitions must be made before July 10, the day of the draw for the quarter-finals and semi-finals of this season's Champions League and Europa League.
The issue has been further complicated by current government quarantine guidelines that require people to self-isolate for 14 days if arriving in the UK, which is under review.
The Football Association has been asked to provide a list of clubs to participate in next season's European competitions by August 3.
The Scottish Football Association, and other associations that ended their season early, had to submit their lists by July 13.
Theodore Theodoridis, UEFA General Secretary, outlined the latest plans in a 10-page document to all 55 associations on June 30.
The correspondence, seen by Sky Sports News, has confirmed:
- Venues for the remaining last-16 games must be at home or at a stadium assigned by UEFA in Portugal, for Champions League fixtures, or in Germany, for Europa League matches;
- Manchester United vs LASK, Wolves vs Olympiakos and Bayer Leverkusen vs Rangers second leg ties must be played on August 5/6;
- Manchester City vs Real Madrid and Bayern Munich vs Chelsea second leg ties must be played on August 7/8;
- Inter Milan vs Getafe and Sevilla vs Roma will be played as single-leg ties after their first legs were postponed in the Europa League.
Champions League quarter-finals, semi-finals and the final will be played in Lisbon, Portugal from August 12-23.
The Europa League knockout games, from the quarter-finals, will be hosted in Cologne, Duisburg, Dusseldorf and Gelsenkirchen, Germany, from August 10-21.
All quarter-finals and semi-finals will be played over one game, instead of two legs.
UEFA has told associations it is still finalising its COVID-19 medical protocols and will issue further guidance "in the next few weeks".
All teams will be required to travel by private jets, rather than commercial airlines, "to protect the health of all participants… when the competitions resume."