The Fire and Rescue Department said two of the four on board were killed. One of the four was a woman.
Witnesses said they saw the two helicopters flying above the Bukit Tabur quartz ridge before one of them began swirling wildly in the air for about three minutes.
The two-seater aircraft crashed to the ground, just 10m from the main water pipe coming from the Klang Gate Dam, at 11.15am. The other helicopter made a crash landing at a school nearby.
A resident, Mohd Irwan Hashim, 42, said he was among the first to arrive at the crash site and saw two people lying motionless inside the cockpit of one of the helicopters.
“We failed to resuscitate them. Soon after that, the ambulance arrived.”
Senior Minister for Economy and International Trade Industry Minister Mohamed Azmin Ali arrived at the scene an hour after the incident.
The Gombak MP said he was glad the helicopters didn’t crash into the neighbouring houses and noted that the area had a high population.
The helicopters were believed to be on their way from Subang airport to Genting Sempah at the time.