Prayagraj: Two labourers were killed and three others sustained serious injuries after a tractor carrying them collided with a speeding SUV near Saray Bhimsen Gate on Patti-Chilbala route under the limits of Kandhai police station of Pratapgarh district late Wednesday night.Police said Sarai Bhimsen resident Vinod Kumar, who operates a concrete-casting machine, was returning home after casting the roof slab of a house in Patti area with a group of labourers. On the Chilbila-Patti main road, he parked his tractor in front of the Sarai Bhimsen gate and was helping the labourers disembark when a SUV rammed into the tractor with great impact.Following the collision, the labourers were trapped between the two vehicles. Two of the labourers, including Shyamu (55) and Pawan (25) died on spot and three of the injured were referred to SRN hospital for treatment.