Cancelling the Giro d'Italia and Tour de France would be a disaster for cycling, says UCI president David Lappartient whose sport has already been badly hit by the coronavirus crisis.
Several races, including the Tirreno-Adriatico and Milan-Sanremo, have been called off as Italy deals with rapidly escalating numbers of infections and deaths.
The Giro d'Italia, the second-biggest race behind the Tour de France, is due to start on May 9 in Budapest, ending in Milan on May 31. Italy's Prime Minister Giuseppe Conte said on Monday all sports events in the country were suspended.
Asked about the prospect of the Giro and Tour de France becoming the latest victim to the coronavirus crisis, Lappartient said: "That would be a disaster for our sport of course if we can't have the Giro d'Italia or the Tour de France."
The Tour de France starts in July and Lappartient expressed some optimism that by that time the worst of the coronavirus outbreak may be over.
"Maybe the gap of two months in between [the Giro and Tour de France] will have also some consequences on the virus," the Frenchman said. "Maybe in summer we hope so, that it will after the summit of the peak, decrease.
"So we hope that these races will be able to take place. But we are, due to the situation in Italy, a little more worried today with the situation with the Giro d'Italia.
"We know what the decision from the Italian government is until April 3, but who knows what will be the situation after. So there is a potential risk that the Giro can be cancelled."
The Giro began in 1909 and has been held every year apart from during the two World Wars while the Tour de France was first held in 1903 and has been contested every year since 1947.
The Paris-Nice race is ongoing, but with infections rising in France, Lappartient said there was a danger that race might have to be cancelled too or fans barred from watching it.
"I hope Paris-Nice can go to the end. This is indeed the goal. But maybe the prefect [French state representative] will have to decide whether or not they close for the finishing area without fans and so on," he said.
"This is not what we want, but if it's the only solution to organise the race, we'll have to go ahead with this. So we are in touch day by day [with race organisers ASO].
"We have to follow the situation with the virus and take the best decision at the moment."