Professional rock climbers are set to challenge Donald Trump’s assertion his border wall was trialled by 20 mountaineers and is “impossible to climb”.

Rick Weber, one of the founders of Muir Valley, a popular rock climbing park and nature reserve in the Red River Gorge area of Kentucky, has arranged a competition for accomplished climbers to ascend a replica of Mr Trump’s wall.

Mr Weber said no one in the climbing community knew any of the 20 mountain climbers the US president referred to.

“We have, I guess you could say, world-class mountain climbers. We got climbers,” Mr Trump said next to a recently completed part of the border in Otay Mesa, California last month.

“We had 20 mountain climbers. That’s all they do – they love to climb mountains. They can have it. Me, I don’t want to climb mountains. But they are very good, and some of them were champions. And we gave them different prototypes of walls, and this was the one that was hardest to climb.”

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Mr Trump boasted the material employed to erect the wall, which is higher than 30 feet, on the southern US-Mexico border is “very powerful concrete”.

Mr Weber announced the climbing contest in an article in esteemed climbing magazine Rock & Ice – saying it would take place on 11 and 12 October on land in the Red River Gorge region next to Muir Valley.

He wrote: “No one in our climbing community knows any of these 20 mountaineers. I doubt if they exist. More importantly, to declare something to be impossible to climb to a bonafide rock climber is to issue a challenge.

“So, I decided to build an exact replica and hold a competition. Although I’m 75 years old, I am still an active rock climber and hold certification by American Mountain Guide Association as a Single Pitch Instructor. It helped that I’m also a retired engineer.”