KUALA LUMPUR: Bukit Aman Special Branch Counter Terrorism Division head Senior Asst Comm Datuk Ayob Khan said the threat of Islamic State was very real.
"It should not be underestimated. We have to be alert at all times," he said.
"Every piece of intelligence is important and could be the difference in preventing any attack on home soil."
SAC Ayob Khan said more than 150 militants had been detained since February 2013.
More than 107 militants have been detained under Security Offences (Special Measures) Act (Sosma) 2012.
He said those arrested came from a wide range of backgrounds.
"Some of them were highly educated individuals, including professionals.
"Among those detained were 17 civil servants," SAC Ayob Khan added.
SAC Ayob Khan said there were still many Malaysian militants currently fighting in Syria and Iraq.
A total of 17 Malaysians have been killed in both countries, six of whom died as suicide bombers.
The latest two to be killed were Mohamad Syazwan Mohd Salim, 31, who, was one of seven suicide bombers who infiltrated a police training centre at the Speicher military base, about 160km north of Baghdad, Iraq, on Jan 3.
Five days earlier, on Dec 29, Mohd Amirul Ahmad Rahim, 26, triggered a bomb strapped to himself in a vehicle during a battle at the Islamic State militants' stronghold at Raqqa, Syria.