Chris Froome strengthened his grip on the yellow jersey with second place as Tom Dumoulin won Friday's stage 13 time trial.

Froome showed no ill effects from the chaotic finish to stage 12 on Mont Ventoux - when he was reduced to running up the mountain on foot following a crash.

The Briton finished 63 seconds behind Dumoulin's stage-winning time of 50 minutes 15 seconds.

The time trial took place in a subdued atmosphere with a heavy police presence following the terrorist attack in Nice on Thursday night.

Bauke Mollema leapfrogged Adam Yates into second place, 1:47 down on the yellow jersey, with Yeats a further 58 seconds behind.

Ireland’s Dan Martin had a tough day in the saddle, losing more than three minutes on the leader, though he hangs on to a top ten spot with ninth place, 5:03 down.

Froome is now in great shape to retain the title he won last year and complete his third Tour de France overall victory.

Nairo Quintana was expected to lose time on this 37.5 kilometre test from Bourg-Saint-Andeol to La Caverne du Pont d'Arcalso and he duly lost out.

The Movistar rider slipped to two minutes and 59 seconds off yellow although the Colombian is still in fourth place.

Twenty four hours before he crossed the line here, Froome had been caught in a chaotic and bizarre end to stage 12 on Mont Ventoux when he crashed along with Mollema and former Sky team-mate Richie Porte when a television motorbike was caught in huge crowds on the mountain.

After briefly racing up the mountain on foot before changing bikes, Froome lost almost two minutes - enough to cost him the yellow jersey - until the race jury intervened and he came out with an increased lead, 47 seconds over Yates.

It was not known if Froome (above) had suffered any injuries in the incident, but there was little sign of that as he turned in a strong ride to increase his advantage.

After the stage, Froome was joined on the podium by the other jersey holders - Yates in the young riders' white, Peter Sagan in the points leaders' green, and Thomas De Gendt in the king of the mountains' polka dots - as well as Dumoulin and several Tour officials to pay their respects to victims of the Nice attack.

At least 84 people, including several children, died after a terrorist drove a truck through crowds celebrating Bastille Day along the Promenade des Anglais.

On Friday morning, Tour officials met with police, government, regional and security officials to discuss security arrangements, and Tour director Christian Prudhomme vowed the race would continue "in sobriety and with dignity".

"We wish today to be dignified, in tribute to the victims," Prudhomme said. "We are thinking about the families, we offer our condolences to everyone who has been affected, who has lost a loved one.

To everyone who is injured, in flesh and in their being."We asked questions of ourselves, effectively. But we think, in agreement with the state authorities, that the race should continue, and we mustn't give in to pressure of people who want us to change our way of life."