Ahmad Zahid Hamidi told reporters Thursday that some detainees had been caught preaching ISIL ideology, prompting police to transfer them to dedicated cells in the vicinity of the same prison complex where they were being held.
"They have been found to influence other criminals in joining the ideology. These are hardcore people who were detained before leaving to fight in Iraq and Syria," the minister told reporters in the administrative capital Putrajaya after a meeting with U.S. Assistant Secretary of State Daniel Russel.
Hamidi said that while police had been carrying out arrests to neutralize ISIL support, many more had left the country to travel to Syria or Iraq.
He said that the latest figures show that 67 Malaysians have gone to Syria and Iraq, five of whom have been killed, while the country has detained some 120 people.
Since February last year, the country has arrested 51 suspected militants who have been accused of trying to flee the country to join ISIL.
The majority Muslim country has also issued a white paper in the parliament to fight a perceived threat of "terrorism-related organizations," predominantly ISIL.
Only last week, Malaysian police had said that religious schools in certain dark Malaysian states to be on the radar, for spreading the IS ideology by preaching the school students to join the "holy cause."
Senior Assistant Commissioner of the Anti-Terrorism Police force Ayob Khan had told The Anadolu Agency that religious schools have been identified as the base for ISIL militant members to spread their beliefs to the students.