The police are not shaken by an Islamic State threat to wreak havoc on Bukit Aman, said inspector-general of police Khalid Abu Bakar.

"Don't try to threaten us. We take this seriously but we (the police force) are too old to be (frightened) by this kind of threats.

"You only dare to make threats from afar, (why don't you) come back!" Khalid said at a press conference in Ampang today.

He was responding to a grim warning from IS in a video released on Tuesday, which also featured a Malaysian fighting in Syria.

“Those of you in Bukit Aman, you will no longer have peace. We will slaughter you... when we return. Our friends back home will hunt you down," said the man police have identified as Mohd Rafi Udin from Negri Sembilan.

Meanwhile, on Special Branch Counter-Terrorism Division chief Ayob Khan Mydin Pitchay's remarks that police were preparing for potential IS attacks within six months, Khalid did not deny such a possibility.

However, he said police have not raised the threat levels, which had been lowered from 'high' after tensions from the January Jakarta attacks eased.

Nonetheless, the top cop said police remained vigilant and prepared, and urged security in public places to be stepped up as well.