At least 17 flood affected people died of burns in southern Pakistan on Wednesday night when the bus they were traveling caught fire as they returning home, officials said.

The incident occurred at M-9 motorway connecting the port city of Karachi with Hyderabad and Jamshoro cities of Sindh province.

“So far, 17 passengers have died in the accident, 10 were injured who were treated by rescue teams,” Siraj Qasim Soomro, parliamentary health secretary told reporters.

Around 35 people were travelling in the bus.

"Those who were travelling in the bus were flood affected people who had relocated somewhere off the motorway, and they were heading back home in Dadu district," Jamshoro District Commissioner Asif Jameel said.

They were using private transport for the purpose, Jameel added.

Dadu district is among the worst flood hit districts of the Sindh province.

It was not immediately clear as to what caused the fire, but police said that apparently the fire erupted at the rear portion of the bus which engulfed the entire bus.

Some passengers jumped out of the bus to escape the fire.

In August 20 people killed in a fiery crash at a motorway in Multan Southern Punjab when it collided with an oil tanker.

Deadly road accidents are common in Pakistan, mainly due to speeding, poor road infrastructure and use of unfit vehicles.

In 2017, an oil tanker overturned and caught fire in the region, killing more than 100 people.