The ministry made the announcement on Saturday in its fourth statement issued about the recent events at the schools.
It said that more than 100 people had been identified, arrested and probed in the provinces of Tehran, Qom, Zanjan, Khuzestan, Hamedan, Fars, Gilan, West Azarbaijan, East Azarbaijan, Kordestan, and Khorasan Razavi.
“Initial inquiries show that a number of these people, out of mischief or adventurism and with the aim of shutting down classrooms and influenced by the created psychological atmosphere, have taken measures such as using harmless and smelly substances”, the statement said, adding that they were cautioned while they will remain under investigation until required assurances are achieved.
Those arrested include individuals who have had “hostile motives, tried to create fear and horror among people and students, shut down schools, and create pessimism towards” the Islamic establishment, the statement by the Interior Ministry further said.
It added that inquiries are underway to find possible links of the second group with terrorist organizations such as Mujahedin Khalq Organization, or MKO.
The statement also said the number of poisoning incidents has been decreasing over the past several days.