Chennai, June 5 : At least three people were killed and five others injured on Monday in a road accident involving four vehicles, police said. The accident that occurred on the Tiruchi-Chennai highway near Perambalur at around 3 a.m., involved a tractor, van, ambulance and a bus First the van collided with the tractor while trying to overtake it. The tractor overturned and the van hit the centre median and came to a halt. A '108' ambulance reached the spot and while its driver and paramedics were involved in shifting the passengers of the van, the speeding bus hit the ambulance and then the median. The victims -- ambulance driver Rajendran, and two paramedics Kavipriya and Kuppuswamy -- died on the spot. The tractor driver and occupants of the van who were injured have been admitted to government headquarters hospital in Perambalur. /IANS