This comes after an investigation launched in August by the Internal Security Agency, Poland's domestic counterintelligence agency, revealed the suspected plot.

According to Polish authorities, the group had planned to send parcels containing hidden explosives and hazardous materials to countries in the European Union and the United Kingdom. These parcels were designed to ignite or explode spontaneously during transit by land or air.

In a statement, the prosecutor’s office said, “The group's goal was also to test the transfer channel for such parcels, which were ultimately to be sent to the United States of America and Canada.”

Canada's national police force, the Royal Canadian Mounted Police (RCMP), declined to elaborate on the matter.

"To preserve the integrity of the investigation, we will not be commenting further at this time," a spokesperson told CBC News.