At least 33 passengers killed and more than 120 injured after Millat Express derailed and Sir Syed Express hit it soon afterwards in Sindh province.
The collision took place early on Monday morning near the town of Dharki, about 440km (273 miles) north of Pakistan’s largest city of Karachi, officials say.
“The number of dead bodies has increased to 33, while the number of injured is near 120,” senior health official Dr Manzoor Jakhrani told Al Jazeera by telephone from one of the main government hospitals were the injured were being treated.
Rescue work is ongoing at the site and is in its “final stages”, he said.
Television footage from the site of the crash showed the mangled wreckage of the two trains strewn across the track, with rescuers using cranes and other equipment to try and reach those trapped inside.