A bus carrying pilgrims has overturned and fallen into a ravine in a remote area in south-western Pakistan, killing at least 20 people and injuring 50 others, officials said.

The accident happened before dawn on Friday in Khuzdar, a district in Baluchistan province, local police official Hafeez Ullah Mengal said.

Rescuers transported the dead and injured to military and government hospitals, he added.

Imam Bakhsh, one of the injured passengers, told the Associated Press that passengers had repeatedly warned the driver to be more careful. He blamed the driver for the accident, saying he was enjoying music and driving recklessly.

Imran Ahmad, an official with the Levies security force, said driver negligence apparently caused the accident, but officers are still investigating.

The pilgrims were returning to Dadu, a district in neighbouring southern Sindh province, after visiting the shrine of a Sufi saint.

Bashir Ahmed, a deputy commissioner in Khuzdar, said the driver lost control on a sharp turn.

He said the bus was overcrowded and several pilgrims were sitting on its roof when the accident took place.

Mr Ahmed said some of the injured were listed in critical condition, and the driver was among the injured.

“There is not a single passenger who does not have an injury because of the bus accident,” Mr Ahmed said.

He added that thousands of people from across the country visit the shrine every year to participate in the annual congregation.

Fatal accidents are common in Pakistan due to poor road infrastructure and disregard for traffic laws. Last month, a bus overturned on a highway in the southern district of Sukkur, killing 13 passengers and injuring 29 others.

The latest accident happened days after at least 65 passengers were killed in a collision of two trains in the southern town of Ghotki in Sindh province.

The collision took place on a dilapidated railway when an express train hit another that had derailed minutes earlier.