The Tour de France is set to be postponed after the French government said no mass gatherings can take place in the country before 15 July due to the coronavirus pandemic.
The 107th edition of the Tour was set to begin in Nice on 27 June and conclude in Paris on 19 July, but President Emmanuel Macron's announcement means it will not be able to do so.
Organisers ASO have already ruled out the idea of attempting to stage the race behind closed doors, and have been speaking to local authorities due to host stages about alternative dates.
The PA news agency has contacted ASO for comment.
Cancellation of the race must also be considered a possibility, but would be a last resort given the Tour's importance to cycling's economy - attracting audience numbers far in excess of any other race.
Cycling's World Tour has been on hiatus since Paris-Nice finished a day early on 14 March, with all subsequent races either postponed or cancelled.
The Tour is the next race left on the schedule.
World governing body the UCI has said it is working with stakeholders to draw up a new road racing calendar for 2020, giving priority to the Grand Tours and one-day Monuments.
The Giro d'Italia, due to begin in Budapest on 9 May, has already been postponed.