Fourteen children were in the van when it caught fire near Qatar Hospital in Orangi Town, police said.
Six children were brought to Civil Hospital burns ward while others were treated at Qatar Hospital.
The children are said to be aged between seven to 10 years.
“Of the six children brought Civil Hospital burns ward, four were sent home after being given immediate treatment and two have been admitted.
The two children who have been admitted suffered severe burns but are out of danger,” said Dr Ahmer, incharge of the burns centre.
Eyewitnesses said the van got stuck in mud after the last child was pick from his house near Qatar Hospital.
“Some children and the driver were trying to push the van when it suddenly caught fire.
The children sitting in the van at the time suffered burns,” eyewitnesses added.
The van driver and residents of the area shifted the children to nearby Qatar Hospital.
As per initial reports, there was a short circuit in the van which led to it catching fire.
Police have ruled out that the fire was caused by a gas cylinder explosion.
“There was a LPG cylinder in the van which is in perfect condition,” police said.