At least 18 labourers were killed and 19 others injured when a tempo carrying them from Karnataka to Pune overturned here on Tuesday, a police official said.

The accident occurred on the Pune-Satara Highway after the Khambatki Tunnel in the Khandala ghats, the official said.

As the tempo zoomed out on an S-shaped stretch on the highway which is a potentially hazardous accident spot, it suddenly struck a barricade and overturned.

Bogged down by the weight of some construction equipment, it was thrown into a wayside ditch with great force, the impact killing many on board instantly, including the driver, according to the official.

The police said at least 36 labourers mainly from Bijapur in the adjoining state were bound for work at a construction site at Shirval, near Pune.

According to preliminary investigations, the tempo driver may have dozed off and many of the labourers suffered injuries on account of the heavy construction material loaded in the vehicle.