Police were on alert Thursday after 11 university campuses around the country received a total 12 envelopes containing a white substance that experts say is used in the production of industrial adhesives.
The Civil Protection Agency also warned post offices and universities against opening any package deemed suspicious.
All the envelopes were reportedly sent from Kerala in southern India and were labeled with the words “Islamic content” written in English.
They arrived in Greece Thursday and on Wednesday.
Each of the yellow envelopes also had a seal and four Indian stamps.
The investigation was initially undertaken by the police’s anti-terror department, while the envelopes were handled by an expert team of the fire department tasked with dealing with chemical and biological threats.
More than a dozen people – university and postal staff – received medical attention as a precaution but none, reportedly, suffered any health problems.
According to the results of a state lab examination, the powder was made of “irritants used in the production and improvement of adhesives and printing ink.”
The targeted campuses were in Athens, the islands of Crete, Lesvos, Cephalonia and Corfu, the northwestern town of Arta, Sparta in the Peloponnese and the central city of Volos.