Forrest Fenn, who hid the treasure chest: Rex

An eccentric art dealer who claims to have hidden treasure worth millions of pounds in the Rocky Mountains says 350,000 people have tried and failed to find to find the riches.

Forrest Fenn, 87, warned it could be “1,000 years from now” before hunters discover the whereabouts of the chest filled with gold nuggets and precious gems.

He revealed in 2010 that he had concealed the bounty somewhere in the 3,000-mile mountain range, and in a subsequent memoir he published a map and a poem said to contain nine clues about the location.

Four men have died looking for the treasure, thought to be worth about about $2m (£1.4m).

Mr Fenn, a former US Air Force pilot and art gallery owner, is bombarded with hundreds of emails a day from people fishing for clues. The millionaire estimates as many as 350,000 have gone hunting for the fortune, but said he had no way of knowing how close they had come to discovering it. “It could be found soon or 1,000 years from now,” he told CNBC.

Mr Fenn, whose gallery in the New Mexico city of Santa Fe attracted frequent visits from celebrities in the 1970s and 80s, initially planned to bury himself with the treasure when he was diagnosed with cancer in 1988. But after he recovered, he conceived the treasure hunt and dropped clues in a 24-line poem in his self-published memoir The Thrill of the Chase.

He said the popularity of the search “has been successful beyond my wildest dreams”.

However, police have accused Mr Fenn of putting lives at risk after fatal accidents involving treasure seekers. Last July, the body of 31-year-old Eric Ashby was pulled from Colorado’s Arkansas River after his raft overturned. His family said he had moved to the state a year earlier to look for Mr Fenn’s bounty.

Story continues

Three other deaths have been linked to the search for the treasure.

The art dealer responded by revealing additional clues on his blog.

“The treasure chest is not under water, nor is it near the Rio Grande River,” he wrote. “It is not necessary to move large rocks or climb up or down a steep precipice, and it is not under a man-made object.

Video: Quest for Elusive Treasure a Multi-Millionaire Claims He Hid

“Please remember that I was about 80 when I made two trips from my vehicle to where I hid the treasure. Please be cautious and don’t take risks.”

Mr Fenn said his main motivation for setting the challenge was to encourage families to spend more time outdoors.

”I wanted to give the kids something to do,” he told Business Insiderin February. “They spend too much time in the game room or playing with their little handheld texting machines.

“I hope parents will take their children camping and hiking in the Rocky Mountains. I hope they will fish, look for fossils, turn rotten logs over to see what’s under them, and look for my treasure.”