ISLAMABAD, Pakistan (AP) _ A passenger train plowed into a second train parked at a rural station in eastern Punjab state Wednesday, killing at least 20 people and injuring 50 others, the state-run news agency reported.

Villagers reaching the station shortly after the crash tore through the wreckage with their hands to reach screaming passengers, the Associated Press of Pakistan said Thursday, quoting eyewitnesses.

The Rohi Express, bound for the capital, Islamabad, struck the other passenger train shortly before midnight Wednesday at the station in Rustam Sargana, about 180 miles southeast of Islamabad, the agency reported.

Emergency workers feared the death toll could increase as rescue workers pried away more of the twisted pieces of metal.

There was no official word on the cause of the crash but the APP quoted unidentified officials at the scene as saying foggy weather was responsible.

The report said Rohi Express apparently should have been switched to separate tracks before reaching the station.

Pakistan's train system is an antiquated one. In the past decade there have been dozens of accidents in which nearly 2,000 people have died.

In the most serious recent crash, a runaway passenger train in March jumped its tracks and slammed into a sand dune, killing more than 135 people. That accident also happened in eastern Punjab.