Chaos at one of pro cycling's biggest races as reckless driving sends riders crashing to the ground

Bike racing can be a very dangerous, hard-hitting sport.

But usually that's not because cars are crashing into the riders.

Things got really dangerous on Sunday at one of professional cycling's biggest one-day races, the Tour of Flanders, in Belgium, when reckless driving sent two cyclists crashing to the ground.

The first incident happened when one of the "neutral service" cars - which normally provide wheels and bikes to riders in case of emergency - struck Jessee Sergent, a rider from New Zealand.

Sergent, who rides for the US-based Trek Factory Racing team, was leading a breakaway group when a car tried to squeeze between him and the side of the road.

But there was not enough space to pass, and the car hit Sergent.

The cyclist was sent flying and crashed hard on the ground.

This GIF, via Sporza, shows what happened:

Sergent's race was suddenly and dramatically over.

His team tweeted that he suffered a broken left collarbone in the crash.

Not long after that, a second incident happened when a neutral-service car slammed into the back of an FDJ team car - which shunted the team car into one of its very own riders, Sébastien Chavanel (via Eurosport):

See more at Sporza and Eurosport.

Check back for updates.