Three Chinese nationals were arrested with 12 gold bars and $800,000 (£650,000) in cash in eastern Democratic Republic of Congo, officials said.
The gold and money were hidden under the seats of the car in which they were traveling, according to Jean-Jacques Bouroussi, governor of South Kivu province.
He added that the arrest of the men remained secret after the release of another group of Chinese citizens accused of running an illegal gold mine in the area.
Eastern Democratic Republic of the Congo has abundant reserves of gold, diamonds and minerals used in the manufacture of mobile phone batteries and electric cars.
This mineral wealth has been plundered by foreign groups since colonial times, and is one of the main reasons the region has been plagued by instability over the past 30 years.
Militia groups control many mines in eastern DRC and their leaders get rich by selling them to middlemen.
Borosi said some of these precious metals dealers have good relationships with influential people in the capital, Kinshasa, which is why the mission to carry out these latest arrests must remain secret.
He added that they were acting on a tip-off, and that the gold and money were not found until after a careful search of the car in the Walongo area, not far from the border with Rwanda.
He did not specifically mention the amount of gold confiscated.
Last month, the governor told reporters that he was shocked to hear that 17 Chinese nationals, who were arrested for allegedly running an illegal gold mine, had been released and allowed to return to China.
He said this undermines efforts to clean up the DRC's murky minerals sector.
Reuters quoted him as saying that they owe the government $10 million in taxes and fines.
The Chinese embassy did not comment on these accusations.
The arrests come as fighting continues in neighboring North Kivu province The Rwandan-backed rebel group has seized large swaths of territory.
last month, The Democratic Republic of Congo said it had filed a lawsuit against Apple over the use of “blood minerals”, prompting the tech giant to say it had stopped sourcing supplies from the Democratic Republic of Congo and neighboring Rwanda.
Rwanda has denied being a conduit for the export of illicit minerals from the Democratic Republic of the Congo.
In their lawsuit, lawyers representing the Congolese government alleged that minerals taken from conflict zones were “laundered through international supply chains.”
They added, “These activities fueled the cycle of violence and conflict by funding militias and terrorist groups and contributed to forced child labor and environmental destruction.”
