Police are hunting down those responsible for spreading "false information" that a van was detonated in Kuala Lumpur.

Kuala Lumpur police chief Amar Singh said the van is believed to have caught fire due to some internal system fault, and did not "explode" as speculated online.

This is after pictures of the incident were circulated online, raising speculation of another terrorist attack in Kuala Lumpur.

"We believe the incident was caused by the van's internal system and that the vehicle was not detonated, as speculated in viral postings," Amar Singh said in a statement late yesterday.

"Kuala Lumpur police will investigate the matter to find the culprit behind the spread of false information," he said.

In his police report on the incident, the driver of the van said he saw smoke coming out of his engine when passing Jalan Bunus 6.

He pulled over and alighted, just before the van caught fire. The flames quickly engulfed the whole vehicle, the KL police chief said.

No one was injured.

The van was on the way to downtown Kuala Lumpur from Kedah

Police on July 4 confirmed the IS had a hand in the grenade attack on a pub in Puchong, making it the first IS attack in Malaysia.