Police said the gang hired couriers in the Czech Republic who traveled in pairs from Prague to Australia, mostly through Los Angeles or Thailand. They always had four pieces of luggage, each containing five kilograms (11 pounds) of drugs.
The drugs could not be detected by X-rays or sniffer dogs, police said, without giving details. They said 60 people have been charged with drug trafficking in the Czech Republic. Four others were arrested in Australia.
The U. S. Drug Enforcement Administration, U. S. Department of Homeland Security and Australian Federal Police have been cooperating on the investigation, which is continuing.