The 47-year-old was said to have been knocked out after he hit his head falling off a motorbike in a remote part of the African country.
It is unknown whether Hammond was wearing a helmet while filming the segment for the next Amazon Prime series but it is believed the TV star laid unconscious in the road miles from medical help.
“Richard was travelling quite fast when he came off. It caused instant horror on set. There was a lot of concern,” a source told The Sun.
“If his injuries had been serious it wouldn’t have been easy to get medical attention.
“It’s very remote there and facilities are basic.”
The incident comes after Hammond almost died in a 288mph collision whilst filming Top Gear 11 years ago.
At the time, his co-star Jeremy Clarkson, admitted: “He really did hurt himself quite badly.”
But when asked if his friend went to hospital, he replied: “We don’t do hospitals.”
With the last crash fresh on their minds, Clarkson, 57, and fellow presenter James May, 54, – who were present at the time – were said to be “shaken” by the incident.
Hammond is now said to be “fine” and the trio are back to having “jokes and banter”.
It is believed the motorbike accident will feature in the second series when it airs later this year.
The father-of-two was airlifted to hospital in September 2006 after driving a jet-powered car, the Vampire dragster.
The crash, that was due to a blowout of the front right tyre, left the presenter with a serious brain injury but the accident was shown on Top Gear four months later when Hammond had made a full recovery.
The Grand Tour will air later this year on Amazon Prime.
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