The Tour de France resumed as planned on Friday but under heightened security as riders observed a moment of silence in tribute to the victims of the terrorist attack in Nice, France.

Thousands of fans lined the roads at the starting line in the town of Bourg-Saint-Andeol, France, amid reinforced security a day after a driver of a large truck plowed into a crowd for a Bastille Day fireworks display in the Riviera city of Nice, killing at least 84 people.

The killings on France’s national holiday followed attacks in November in Paris that killed 130. France has declared three days of national mourning after the attack in Nice.

Defending champion Chris Froome of Britain extended his overall lead to one minute and 47 seconds by finishing second Friday in the 13th stage time trial over the 23-mile leg from Bourg-Saint-Andeol to La Caverne du Pont-D’Arc in the Ardeche region.

Froome, seeking his third Tour title in four years, tweeted a picture of the blue, white and red French flag.

“Thoughts are with those affected by the horrific terror attack in Nice,” Froome wrote on Twitter.

Dutchman Tom Dumoulin won the stage in 50 minutes and 15 seconds, with Froome clocked in 51 minutes and 18 seconds.

“It’s terrible what happened and overshadows the day a lot,” said Dumoulin, who also won a mountain stage last week in the Pyrenees. “So you’re speaking to a man with two sides to his face today. Of course I’m happy with the win, but at the same time my thoughts are with everyone involved in the horrific attacks in Nice.”

The 31-year-old Froome leads Dutch rider Bauke Mollema by 1:47 overall, with fellow Briton Adam Yates in third place, 2:45 back. Two-time runner-up Nairo Quintana of Colombia is fourth, 2:49 behind.

“Today, we want to pay homage to the victims with dignity,” tour director Christian Prudhomme said. “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.”

Froome, who lives in Monaco, just 12 miles from Nice, said: “This is definitely a time for people to stand together. It definitely puts things into perspective for us. I’m happy with how the stage went but everyone’s thoughts are with the people in Nice. It’s a special place for me, close to where I’m based, and I can’t imagine what everyone is going through.”

Friday’s stage is a 23.5-mile time trial from Bourg-saint-Andeol to Vallon Pont-d’Arc in the Ardeche region about three hours northwest of Nice.

The Tour ends on July 24 in Paris on the Champs Elysees.