A collision involving two trains in the Pakistani city of Karachi has left many victims. The number of people known to have been killed has been rising – by the middle of the day local time some reports were speaking of over 20 dead.

An express train is said to have sped into a railway station, ramming into a second train which was stationary.

It’s thought there may have been up to a thousand passengers in both trains. Witnesses have described the screams of people trapped inside.

People rushed to help. Passengers were pulled out, but at least one rescuer said many others couldn’t be reached.

Dozens of injured were taken to hospital. But in the aftermath of the crash, ambulances got stuck in traffic jams which developed.

Train services from Karachi to the rest of the country were suspended.