FAISAL KAREEM / EPA
Imran Shah, a spokesman for highway police, said authorities had tried to keep onlookers away from the site but were ignored.
The driver of the tanker survived the accident and had been taken into police custody, he said.
Baqar said many of the bodies were burned beyond recognition and will have to be identified through DNA testing.
Some of the most badly burned were evacuated by army helicopters to Multan, about 60 miles away. The dead included men, women and children.