At least 30 people died and 50 were injured after two passenger trains collided in Pakistan’s Sindh Province on Monday morning, Dawn reported. The number of casualties is expected to increase.

The Millat Express train, which was travelling from Karachi to Sargodha, derailed and fell on the opposite track, a Pakistan Railways spokesperson said. It then collided with the Sir Syed Express which was travelling from Rawalpindi.

The collision occurred near Dharki in the Ghotki district of Sindh. Ghotki Deputy Commissioner Usman Abdullah said that six to eight compartments were completely destroyed in the accident, while 13 to 14 had derailed.

Rescue operations are underway, and an emergency was declared in hospitals in Ghotki, Sharki, Obaro and Mirpur Mathelo, according to news agency PTI. However, officials have reported difficulties in reaching people trapped inside the overturned train compartments. Around 15 to 20 passengers are reportedly still trapped in the wreckage.

“This is a challenging task. It will take time to use heavy machinery to free citizens [still trapped],” Abdullah said. “We are also establishing a medical camp to provide medical aid to citizens.”

Pakistan Prime Minister Imran Khan expressed his condolences and ordered an investigation. “Shocked by the horrific train accident at Ghotki early this morning leaving 30 passengers dead,” he said. “Have asked Railway Minister to reach site & ensure medical assistance to injured & support for families of the dead. Ordering comprehensive investigation into railway safety faultlines.”