The Strade Bianchi, the first big race of the Italian cycling season, was cancelled on Thursday due to coronavirus outbreak while other races including the Milan-San Remo classic were under threat.

Ahead of this weekend's start of the Paris-Nice race, French officials established new rules ordering riders to stop signing autographs, imposing a selfie ban, and scaling down the traditional end-of-day award ceremonies with hostesses banned.

The organisers of the Strade Bianche met with officials in Siena, where the race starts and ends. They concluded that the race could not guarantee meeting the provisions of an Italian government decree issued the day before ordering all major sporting events be held behind closed doors until April 3.

Both the men's and women's races, scheduled for Saturday, were cancelled.

Over the previous 48 hours, several teams had withdrawn from the race, including Mitchelton, EF, Jumbo, Groupama-FDJ and Ineos.

The organisers said on the race website that they would seek new dates from the International Cycling Union (UCI).

For the time being, there has been no decision on the two other World Tour races scheduled for the coming weeks in Italy, Tirreno-Adriatico (March 11-17) and Milan-San Remo (March 21).

But the Paris-Nice stage race starting Sunday is set to go ahead minus some top teams who have put the health of riders, officials and spectators ahead of other considerations.

Mitchelton and Ineos were joined Thursday by Astana in announcing they were pulling out of the race.

New guidelines issued 

Under pressure to reassure teams, the UCI has issued new guidelines for riders and organisers as more races came under threat.

The body ordered organisers to prevent mingling and keep riders further away from the public during and after races as part of regulations designed to curb opportunities for the spread of the coronavirus.

The Italian races have already been hit by major defections and are judged most vulnerable to cancellation.

Half the field -- Mitchelton, EF, Groupama-FDJ, Ineos, Astana, UAE, AG2R La Mondiale, Sunweb and Jumbo -- have pulled out of the Tirreno-Adriatico set to start next Wednesday.

And AG2R La Mondiale said it will not race in Italy at least until after the classic Milan-San Remo.

Astana general manager Alexander Vinokourov said concern for the health of the team came first.

"We have chosen to protect the health of our riders and staff and to take our responsibility for the society in not further spreading the virus," he said.

The first cycling victim of the virus fell last week when the UAE Tour was cancelled after two Italian staff members on the race tested positive for the COVID-19.

Cyclists, team staff and some media were put under lockdown at hotels in Abu Dhabi where they underwent screening.

While most teams have been cleared to leave, two French teams, Cofidis and Groupama, are kept in quarantine in the UAE until March 14.