Two Australian men were arrested by PJ police at Lisbon airport while trying to leave for Paris with six rhinoceros horns valued at around €400,000.
The police suspect that they are part of an international crime network which has been carrying out this type of theft at museums throughout Europe.
PJ police, in conjunction with Europol and Interpol, had conducted a surveillance operation.The men also had with them €50,000 and some Pounds Sterling.
The trafficking of rhino horns has become a more profitable crime business than diamonds or drugs, with prices of around €50,000 per kilo.
The destination is almost always the Asian market, especially China and Korea, where the horns are reduced to powder for medicinal or aphrodisiac products.
Dozens of thefts of rhino horns have been recorded in several European countries in recent months, leading some museums replacing the real horns with replicas.