Tungsten ore mined by a terrorist group in Colombia ends up in cars built by BMW, Ferrari and Volkswagen, a Bloomberg Markets magazine investigation says.

The ore, also known as wolframite, is illegally mined in the Amazon jungle by the FARC rebel group, which is classed as a terrorist organization by the United States and European Union, according to the report.

After the ore is processed in Pennsylvania, it is shipped to Austria, where it is used to produce tungsten that goes into engine crankshaft parts, the report said.

BMW and Volkswagen told Bloomberg Markets they avoid purchasing anything from tainted suppliers, while Ferrari had no comment.

Tungsten ore mined illegally in Colombia passes through a supply chain to European automakers, according to the investigation.