The drugs, with an estimated street value of PLN 48 million (around EUR 11.2 million, USD 12.8 million), were discovered in two shipping containers routed from Thailand through the German port of Hamburg to Poland, according to Poland's Border Guard agency.
Six of the suspects, aged between 29 and 57, have been placed in pre-trial detention for three months. One suspect was released after questioning, while another was placed under police supervision pending further proceedings.
Interior Minister Marcin Kierwiński described the operation as the Border Guard's largest anti-drug seizure in recent years.
The Border Guard has significantly expanded its role in combating organized drug crime in recent years, Kierwiński said on Thursday.
He added that the force had seized nearly 2 tonnes of various narcotics worth almost PLN 100 million over the past six months alone, as part of broader efforts against international trafficking networks.
The operation, carried out by officers from the Border Guard's Maritime Unit in the Baltic port city of Gdańsk, dismantled what investigators described as an organized criminal group that established a cross-border smuggling route from Thailand through Germany into Poland.
Authorities said the crackdown came through international cooperation under a European Investigation Order, involving German customs officials in Hanover, a joint anti-drug task force in Oldenburg, northwestern Germany, and the European Union's Europol and Eurojust agencies.
Investigators said the first container, inspected in Germany's Hamburg, contained 815 kilograms of marijuana hidden inside specially modified laterite bricks.
A second container destined for the same recipient in Poland contained another 379 kilograms, bringing the total seizure to 1,194 kilograms.
The first arrests were made on May 6 in the northwestern Polish city of Szczecin, where officers detained four men, including the owner of the company that was to receive the shipment, during an attempted unloading.
Four more suspects were detained near the western city of Poznań on June 15.
Prosecutors have charged the suspects with importing and smuggling large quantities of narcotics within the European Union. Three also face charges of participating in an organised criminal group. The offences carry prison sentences of up to 20 years.
Border Guard Commander Gen. Robert Bagan said the force, working with customs authorities and the Central Bureau of Police Investigation (CBŚP), had seized around 3 tonnes of narcotics worth more than PLN 200 million over the past 30 months, including cocaine, hashish, marijuana, amphetamine, methamphetamine and mephedrone.
The investigation is being overseen by the National Public Prosecutor's Office's organized crime and corruption unit in Gdańsk.
The case is ongoing and further detentions are possible, officials said.
(gs)
Source: IAR, PAP