The security presence at the Tour had already been strong but was noticeably increased for Friday's time trial between Bourg-Saint-Andeol and La Caverne du Pont d'Arc in the wake of the attack.

On Friday, Tour officials met with representatives from the police, security forces and local government to discuss security arrangements before announcing the race would continuity "in sobriety and with dignity".

But there was a very different mood at the Tour as the peloton reflected on the day's events.

A large number of riders live around Monaco and Nice and know the area well - giving them a personal connection to the tragedy.

Chris Froome strengthened his hold on the yellow jersey on Friday but kept his focus on Nice after the race.

"I gave it my everything today but my thoughts are a little bit elsewhere," he said.

"I just couldn't believe the images I was seeing coming out of Nice. It is somewhere quite special to me. The promenade where we ride up and down, to see it the way it was with bodies after the attack, they were horrific, horrific scenes and it definitely puts things in perspective for us."

But even with security ramped up, the chaos on Mont Ventoux on Thursday showed just how vulnerable an event such as the Tour de France is.

Absolute chaos at the death as Porte crashes into camera bike. Froome sent tumbling and opts to run. #TDF2016 https://t.co/0k0XBSEYb3

— Eurosport (@eurosport) July 14, 2016

Froome was left to run up the road on foot after his bike was broken in a crash caused by a television motorbike being forced to stop by the thick crowds on the mountainside.

The huge numbers of fans who usually assemble on the race's most famous climbs are given the freedom of the roads for all but the final few kilometres, but one of cycling's greatest selling points is becoming an increasing risk given the difficulty of protecting the riders.

"The fans are a big part of the sport," said Froome's Sky team-mate Mikel Landa. "It's a concern, but we love having them there. We have to find a balance."

On Wednesday evening, organisers had announced their decision to shorten Thursday's stage by six kilometres due to gale-force winds at Ventoux's exposed summit, but in the difficult conditions that left insufficient time for the barriers which usually protect the final few kilometres of a stage to be moved down the mountain - with only around 600 metres protected.

The shortening of the stage also saw fans compacted into a smaller section of roadside - leading to the inevitable squeeze.

Fabian Cancellara, whose Trek-Segafredo team-mate Bauke Mollema was caught in the same crash as Froome, said he had been left "angry" by what happened on Ventoux.

"Yesterday the feeling was not even from the fans one of support," the 35-year-old Swiss, in his final season as a professional, said.

"It was actually the opposite. I was alone and could not go through all these people. It was like a football pitch with lots of hooligans. This is not nice. This is an open sport where you can come and see and there are families and kids, and cycling should not have this image."

Cancellara pointed the finger at the organisers, and demanded more be done to protect the race and the riders in the current climate.

"For sure there is big blame towards the organisation," he said.

"The Tour is big. Maybe yesterday it was too big and they have a lot of negatives. When you look at what happened in Nice it is even more important there is more safety for us on the road.

"Sometimes it's not even a race, it's just the name of the race that is big, and that means we are just the clowns."