A former Russian diplomatic official and a police officer in Argentina are among those arrested after nearly 400 kg of cocaine was seized at Moscow's embassy in Buenos Aires.
The drugs were found in diplomatic luggage in December 2016 after the Russian ambassador to Argentina raised the alarm.
While still at the embassy, the cocaine, valued at 50 million euros, was replaced with flour by authorities in an unprecedented joint investigation between the two countries.
Argentina's Security Minister Patricia Bullrich said the probe saw tracking devices put in the bags, apparently bound for a diplomatic flight.
At least five people have been detained in connection with the investigation.