Armenian authorities say a former deputy defense minister has been detained in connection with the investigation into a shadowy group that allegedly was stockpiling weapons and ammunition in preparation for attacks on politicians.

A statement from the national security service on Saturday said Vaan Shirkhanian was being held on suspicion of participating in a criminal organization. It said the alleged organization was headed by Artur Vardanian, who was said to have lived in Spain for many years.

Vardanian and 20 other suspects were arrested in November and police said the group had an array of weapons including firearms and grenades.

Armenian news reports have said the Vardanian group is suspected of preparing attacks on politicians and officials, but details have not been made public.