Paris-Roubaix race director Thierry Gouvenou has named increased speed as one reason for a growing number of crashes at major cycling races.
"Stop, stop, stop, let us end the massacre. Let's start to think about the speed problems," Gouvenou told sports paper L'Equipe ahead of Sunday's edition of his race.
"We've made enormous progress in aerodynamics and braking. We're going far too fast."
Gouvenou spoke after a heavy crash in the Itzulia Basque Country stage race where Tour France champion Jonas Vingegaard and Remco Evenepoel were among casualties in a mass crash on Thursday and suffered fractures.
"I hope that the riders who crashed in the Basque Country will come out OK. But it really is time to set limits," Gouvenou said.
"We've been warning everyone for months now. The race organisers are putting many things in place.
"But we've noticed that the number of crashes is only increasing. So we have to realise that the falls are not just due to the course. In my opinion, and as a former racer, they are due to speed.
"Unfortunately, as soon as you leave the road, you're not protected because you're cycling on the same road as everyone else. You could come up against a tree, a pole or a large stone. And every time you go out, you have to rely on luck to get you through.
"The drivers (of cars) in the races, who are very experienced people, tell me that they no longer have a margin of safety when they descend in front of the riders. The descents in the mountain passes are done at more than 100kph."
Gouvenou's race on Sunday has taken some precautions, most notably adding a chicane ahead of the most difficult cobblestone section at the Arenberg forest in order to slow down the speed.