PINAMAR, Argentina — A former Russian diplomatic worker and an Argentine police officer were among six people arrested on Thursday after a 14-month investigation triggered by the discovery of hundreds of pounds of cocaine at the Russian Embassy in Buenos Aires.

“We have dismantled an international cocaine trafficking organization operating between Argentina, Russia and Germany,” Patricia Bullrich, Argentina’s minister of security, said in a televised news conference.

She said the seizure of 389 kilograms of cocaine, more than 850 pounds, was made at a school on the grounds of the embassy in December 2016, leading to an investigation by Argentine border guards, the Buenos Aires police and the Russian Interior Ministry. The cocaine, she said, was valued at more than $60 million.

The Russian ambassador to Argentina, Víktor Koronelli, and three members of Russia’s Federal Security Service alerted Ms. Bullrich on Dec. 13, 2016, to what they thought were 16 pieces of luggage filled with drugs.