Officials on Friday said the death toll could rise to as high as 200, as rescue workers picked through charred buses, cars and lorries in the gruesome task of collecting body parts.
"Ninety bodies have been recovered, but the death toll could rise further," a Red Crescent official in Zahedan, the capital of Sistan-Baluchestan province, told Iranian media.
He said 114 injured had been evacuated from the scene of the accident, which occurred at a police post near Nosrat Abad, some 110 km west of Zahedan late on Thursday night.
The flames engulfed six buses and five other trucks, two of which were carrying tar, causing a massive fire, the television said.
Officials expect the number ofl
dead to rise to 200
The accident happened at 22:30 (18:00 GMT) on Thursday when the tanker apparently ran out of control and collided with buses full of passengers that had stopped at the police station.
Lorries and buses often wait outside police stations on highways in southeastern Iran to be inspected for drugs and other contraband.
The lorry was carrying 18,000 litres of petrol.
The official IRNA news agency said most of the dead were women and children who had stayed in the passenger buses while their husbands were being searched by police.
State television showed footage of carbonised bodies lying
amidst a scene of total destruction.
Iran has one of the world's worst rates for road accidents. There were more than 400,000 crashes and 21,000 deaths on its roads in 2002.
The high figures are blamed on unsafe vehicles, disregard of traffic laws and inadequate emergency services.