BANGKOK, Jan. 15 (Xinhua) -- Two people were killed and two others sustained injuries after a construction crane collapsed onto a highway in Thailand on Thursday, authorities said.

The accident occurred at around 9:10 a.m. local time on Rama II Road, the key thoroughfare linking Bangkok and Samut Sakhon province, where the crane operating at an elevated expressway construction site collapsed onto passing vehicles.

Rescue efforts and an investigation into the cause of the collapse are underway.