Three Chinese nationals have been arrested with 12 gold bars and $800,000 (£650,000) in cash in eastern Democratic Republic of Congo, officials said.
The gold and cash were hidden under the seats of the car they were traveling in, according to Jean-Jacques Pourussy, governor of South Kivu province.
He said the operation to arrest the men was kept secret after the recent release of another group of Chinese nationals accused of running an illegal gold mine in the area.
Eastern DR Congo is rich in gold, diamonds and minerals used to make batteries for mobile phones and electric vehicles.
This mineral wealth has been plundered by foreign groups since the colonial era and is one of the main reasons why the region has been plagued by instability for the past 30 years.
Militia groups control many of the mines in eastern DR Congo, and their leaders get rich by selling them to middlemen.
Purussi said some of these precious metals traders enjoy good relations with powerful people in the capital Kinshasa and therefore the mission to make these latest arrests should be kept quiet.
He said they were acting on a tip-off and that the gold and cash were only found after a thorough search of the vehicle in the Walungu district, not far from the Rwandan border.
He did not say exactly how much gold was seized.
Last month, the governor told reporters he was shocked to hear that 17 Chinese nationals who had been arrested on charges of operating an illegal gold mine had been released and allowed to return to China.
He said it was undermining efforts to clean up DR Congo's notoriously murky mineral sector.
They owed $10 million in taxes and fines to the government, Reuters quoted him as saying.
The Chinese embassy has not commented on the allegations.
The arrests come as fighting continues to rage in neighboring North Kivu province, where a The Rwandan-backed rebel group has seized large swaths of territory.
last month, DR Congo says it is suing Apple for its use of “blood minerals,” prompting the tech giant to say it has stopped receiving supplies from both DR Congo and neighboring Rwanda.
Rwanda has denied being a conduit for the export of illegal minerals from DR Congo.
In their legal action, lawyers acting for the Congolese government alleged that minerals taken from conflict zones were then “laundered through international supply chains”.
“These activities fueled a cycle of violence and conflict by funding militias and terrorist groups and contributed to forced child labor and environmental devastation,” they said.