More than 30 riders were disqualified from the U23 Giro d'Italia after they were caught on camera hanging onto team cars and motorbikes on the famous climb of the Stelvio Pass.
The race jury excluded 24 riders on Wednesday night after reviewing videos taken by fans, and disqualified a further seven on Thursday morning.
Wednesday's fourth leg was the "Queen stage" of the race, which has been rebranded as the Giro Next Gen. It ended with the prestigious and difficult ascent of the Stelvio.
Fans lined the sides of the climb and the riders appeared not to notice they were being filmed as they flagrantly broke the rules, with some chatting and laughing among themselves as they clung onto the sides and back of team cars.
Of the riders disqualified, 24 were Italian and seven were foreign, including Belgian cyclist Tijl De Decker, who won this year's Paris-Roubaix U23. Four team staff members and their team cars were also excluded from the race.
"What we saw was really offensive to those who correctly interpret this sport," Italian cycling federation president Cordiano Dagnoni said on Thursday. "They are images that really hurt.
"It's right to apply the rules and I'm above all disappointed by the behaviour of the sporting directors in the team cars, because they should be the first to teach the youngsters how to respect the rules."
The riders and teams could face further punishment from the federation or even the International Cycling Union.
ASD GC Sissio team had four of its five riders turfed out, while fellow Italian teams Ciclista Rostese and Technipes lost three riders apiece.
"I asked [race organizers] RCS Sport to invite at least half Italian teams," Dagnoni said. "At this point, having seen the behavior of our teams and of our cyclists, I no longer feel like recommending they be invited in the future. I will leave RCS Sport free to invite teams at their discretion."
