The Tour de Suisse was cancelled on Friday in the face of the coronavirus pandemic and the organisers of June's eight-day cycling race said they will not reschedule it for later in the year.
"This is the first time since the Second World War that the traditional event will not take place," said the statement on the race website, noting that Swiss authorities had not yet banned the event.
The tour, scheduled for 7-14 June, had been the earliest top-level race still standing on the cycling calendar.
The organisers listed a series of potential problems if it went ahead.
These included the "support from the army and police for the safe execution of the event," travel restrictions for teams from other countries and the risk of "additional strain on the Swiss health system due to possible crashes".
They said the lack of preparation of riders based in countries where outdoor cycling is prohibited meant "a fair competition cannot be guaranteed".
The statement also said the cancellation was a financial necessity because the pandemic has brought a collapse in sponsorship and in sales of hospitality packages. Further delays "would result in increased costs" for the organisers, sponsors and host cities.
"The top priority of the Tour de Suisse organisation is to ensure the continuity of this event," said the statement.
The statement said that the organisers were staging a "digital" tour on the same dates and that 17 professional teams had signed up.
Cycling is in shutdown until the end of May, with the Tour de France still due to start on 27 June.