The 25-year-old was involved in a crash in Sainte-Marie-Cappel, with around 115 kilometres of the International Cycling Union (UCI) World Tour race remaining.

Four other riders were also involved in the crash, as the Belgian race briefly entered northern France.

While on the ground, Demoitié was reportedly struck by a race motorbike, with the cyclist transferred to a hospital in Lille following the collision.

His pro-continental team Wanty-Groupe Gobert tweeted last night that his condition was “extremely serious” and that he was in the “intensive care unit” at a university hospital.

"The rider died,” Frederic Evrard, a spokesman for the French police, told the French news agency AFP.

“An inquiry is under way to determine the circumstances.”

The UCI stated that they were "extremely saddened to learn about the passing of Belgian rider Antoine Demoitié of Wanty-Groupe Gobert".

"Antoine will be truly missed," said Brian Cookson, UCI President.

"Our thoughts are with his family, friends and team."

The governing body stated they would "cooperate with all relevant authorities to investigate the circumstances of this tragic incident".

World champion Peter Sagan won the men’s race for the second time, with the Slovakian out-sprinting Belgium’s Sep Vanmarcke from a breakaway to claim the victory in a time of five hours, 55min and 16sec.

The Netherlands’ Chantal Blaak soloed to victory in the women’s race, after a breakaway 10km from the finish, to take over as the Women’s World Tour leader.

Tributes have been pouring in from the world of cycling.

Demoitie's team-mate Mark McNally tweeted: "There are no words to describe this tragedy."

Double Olympic gold medallist Geraint Thomas said: "Incredibly sad news this morning.

"My thoughts with Antoine Demoitié's loved ones and team-mates."

Wanty’s press officer, José Been, refused to blame the motorbike rider involved in incident.

“This is a tragic accident with a driver who’s been in Belgian cycling races for at least 20 years,” Benn told Het Laatste Nieuws.

“He is very affected by what happened, just as we all are.

“This is not a case of collision at high speed such as the ones with Peter Sagan or Stig Broeckx.

“This is a fatal accident – the man tried to brake and fell on Antoine.”

Gianni Bugno, President of the CPA - the International Association of Professional Cyclists - expressed his frustration following Demoitié's death.

“At this time of sadness and sorry for the death of Antoine we do not want to make much controversy, but we have so much frustration inside,” he said in a statement.

“We have always stated that the safety of the riders must be in first place in the discussions of the cycling stakeholders and at the last Professional Cycling Council meeting we have specifically asked to communicate fast the strategies developed recently to improve security during the races.

“I do not want to accuse anyone but make everyone reflect on the responsibility we have to ensure that it is always maintained a very high level of attention, awareness, and control over safety standards during each race.”