Multan (Pakistan) (AFP) - At least four people were killed and more than 100 injured when two trains collided in central Pakistan early Thursday, officials said.

The accident occurred when the Karachi-bound "Awam Express" passenger train rammed into a goods train that had stopped after running over a man near the city of Multan.

Rescue workers used metal-cutting equipment to try to reach injured passengers still trapped in the mangled wreckage, according to an AFP reporter at the scene.

Mohammad Javed, 35, a shopkeeper who lives near the site of the crash said he had been woken up by "a huge blast".

"I thought that some bomb had exploded," he told AFP.

"I came out of my house and saw a passenger train had piled up on a goods train. I heard people crying in pain and many lying outside the train.

"Survivors and locals were pulling out wounded people who were stuck in the wreckage."

Local state-run rescue service spokesman Abdul Jabbar told AFP that more than 100 people had been hurt.

Railway official Saima Bashir blamed the accident on the passenger train driver, saying he failed to heed a red signal that went up after the goods train had stopped.

Cranes and ambulances filled the area as troops also raced to the scene to help.

Rescue official Khalid Hussain 28 people had been taken to hospital, while scores more were treated on the spot.

A three-day public holiday for the festival of Eid ul-Adha ended on Wednesday, and many Pakistanis are returning from their family homes to the cities where they work.

Train accidents are common in the country, which inherited thousands of miles (kilometres) of track and trains from former colonial power, Britain.

The railways have seen decades of decline due to corruption, mismanagement and lack of investment.

Last November, 19 people were killed in southwestern Baluchistan province after a train's brakes failed and it sped down the side of a mountain.

In July 2015, at least 17 people were killed when a military train fell into a canal after a bridge partially collapsed.