The Tour de France rode on as planned Friday, with thousands of fans lining the roads and amid reinforced security a day after the deadly attack in Nice.

France was reeling again after a large truck mowed through a crowd of revelers gathered for a Bastille Day fireworks display in the Riviera city of Nice, killing at least 84 people on Thursday night. The attack, on France's national holiday, followed attacks last November in Paris that killed 130.

But the carnage did not deter fans from showing up in numbers at the starting line in the small town of Bourg-Saint-Andeol.

"We can't let our guard down, but it was important that they continued the race," said Bruno Pruvost, a 56-year-old fan. "Otherwise, it would be too easy for them."

Defending champion Chris Froome, the race's current leader, posted a picture of the blue, white and red French flag on Twitter on Friday and wrote: "Thoughts are with those affected by the horrific terror attack in Nice."

Froome was scheduled to compete in the race's first time trial later Friday after organizers decided the hilly 23-mile leg to La Caverne du Pont-D'Arc in the Ardeche region will go ahead following an emergency meeting with authorities.

There was a moment of silence at the start, several hours drive from Nice, and Tour director Christian Prudhomme said there will be a ceremony with a minute's silence at the finish as a tribute to the victims.

"Today, we want to pay homage to the victims with dignity," said Prudhomme, wearing a black armband around his blue shirt and holding back tears. "We have been asking ourselves if the race should continue and after consulting with authorities we have decided that it should. The Tour de France will continue in a subdued and solemn manner."

The publicity caravan, which precedes the riders on the stage route everyday handing out free gifts and souvenirs and blasting loud music, rode silently Friday.

Security had already been reinforced at the Tour this year, with France in a state of emergency since the Paris attacks. The three-week race is protected by an unprecedented force of 23,000 police officers, including SWAT-like intervention squads, while security guards perform bag checks and pat downs at the start and finish of every stage.

Eric Luzet, the police's liaison officer to the Tour, told The Associated Press that extra security measures were implemented overnight, with 600 police officers in charge of security for the stage.

"We have adjusted our measures after what happened in Nice," Luzet said. "They have been deployed at the start and finish of the stage, and along the 37.5-kilometer of the route."

Bauke Mollema, who was involved in a crash with Froome inside the last kilometer of Thursday's Stage 12 at Mont Ventoux when a TV motorbike was forced to stop on the road because of fans congestion, said his "thoughts are with the people in Nice."

Froome was awarded the same time as Mollema after he was forced to wait for a replacement bike following the incident, a decision that left Mollema unhappy. But the Dutch rider put his rivalry with Froome aside.

"I couldn't sleep yet and now read about something more important than the Tour," Mollema wrote on Twitter. " ... crazy world."

French climber Romain Bardet also expressed sadness over the attack.

"Being French, gathering, celebrating, loving each other," he posted on social media. "And never giving up. I'm thinking about Nice."

After 71 riders reached the finish, Portuguese national champion Nelson Oliveira had an early best time of 51 minute, 46 seconds. Froome will be the last starter as he wears the yellow jersey with a 47-second lead over Adam Yates.

Edward Theuns, a Belgian rider with the Trek-Segafredo team, dropped out of the race after a crash and was taken to the hospital while French competitor Thibaut Pinot did not start after catching a cold in the Pyrenees.