According to a tweet by the Malaysian Highway Authority (LLM), only the right lane is passable. Motorists are advised to exercise caution when passing the area.

The incident has also caused a traffic crawl from Setiawangsa to MRR2.

“Please use an alternative route,” LLM said on Twitter.

Ampang Fire and Rescue station operations commander Razali Budin said so far, only one victim, Azri Yahya, had been reported injured.

The man, in his 40s, was sent to Ampang Hospital for treatment.

Razali said the station had received a report on the incident at 10.12am and a team of seven firemen was sent to the scene.

According to him, a crawler crane which was lifting a casing pile for construction work on high ground next to the MRR2 (Ampang-bound) lost its balance and collapsed.

“This caused the crane boom to fall across MRR2 and block two of the three lanes, disrupting traffic flow.”