Kevin Mayer has branded the World Athletics Championships in Doha "a disaster", citing the heat and a lack of fans.
The world champion decathlete did not hold back as he criticised the decision to award the event to the Qatari capital.
Frenchman Mayer suggested it was only his "passion" for competition that prevented him from boycotting.
"We can all see it's a disaster, there is no-one in the stands, and the heat has not been adapted at all," he said.
"There have already been nearly 30 withdrawals in the women's marathon. It's sad.
"We have to leave reason aside and more concentrate on the passion, because if not I would have boycotted these championships.
"We haven't really prioritised athletes when organising the championships here. It makes it difficult."
The IAAF released a statement on Saturday insisting the local organising committee had "done everything possible to minimise the heat-related risks".
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