They valued the seizure, one of the biggest of illegally mined coltan in Colombia in years, at $1.2 million.

The police said the minerals, which are mined together, were extracted by dissident members of the now-defunct rebel FARC army in the jungle near the Venezuelan border.

The shipment seized in the city of Villavicencio came from illegal mines in the remote eastern departments of Guainia and Vichada.

It was bound for the Caribbean port of Cartagena with China as the final destination, the environmental protection police said in a statement.

Left-wing guerrillas and criminal groups exploit Indigenous people in Guainia and Vichada to extract coltan for approximately $7 per kilogram (2.2 pounds).

By the time the mineral reaches the capital Bogota, its value has reached $20, and doubles again in price upon reaching markets in Asia and Europe, according to Colombian authorities.

Coltan is a mineral from which tantalum, commonly used in electronics such as mobile phones and laptops, is derived.

Illegal coltan mining is a key driver of the conflict in Democratic Republic of Congo.

Colombia's defense ministry said six people were arrested over the haul which marked a "decisive blow" to the finances of criminal groups engaged in the plundering of natural resources.

Criminal groups in Colombia finance themselves through the illegal mining of coltan, tin, and gold, as well as cocaine trafficking.

Some also engage in racketeering and migrant smuggling.