Guinea's government says commercially viable reserves of uranium have been discovered for the first time.
Enriched uranium is used for nuclear power generation and weapons
Information Minister Justin Morel Junior announced that samples of uranium were extracted by a mineral company in Firawa.
A BBC correspondent says Guinea is hoping to cash in on the strong global demand for uranium as a nuclear fuel, which has led prices to boom.
The West African nation already has a third of the world's bauxite reserves.
"The government has the pleasure of officially announcing the discovery of uranium deposits in Guinea," Mr Morel said on national television.
A mine official told the BBC's Alhassan Sillah in Conakry that uranium could be extracted soon, although he could not give any specifics.
Our correspondent explained that the discovery could bolster the Guinean economy.
"It will be good for a country in which people have been reduced to beggars," he said.
Most of the population lives on less than $1 a day.
An official told Reuters news agency that Australia-based mineral exploration company Murchison United had made the discovery.
Firawa, where the uranium reserves were found, is in the southern region of Kissidougou, about 600km east of the former French colony's capital, Conakry.
Murchison had been drilling there in May.
"At this stage the genesis and delineation of the uranium mineralisation is unclear," the company said in a statement, last week.
Murchison said it had sent samples of the uranium to laboratories in Mali and Canada.
"Additional samples have been collected from sections indicating the highest radiation, in order to further examine the clay minerals and assess optimal methods of uranium extraction," the statement explained.
Guinea has other natural resources like diamonds, gold and iron ore, and is the second largest producer of bauxite - the ore used to make aluminium - after Australia.