Two passenger trains collided in Pakistan’s southern Sindh Province early Monday morning, killing at least 50 people and injuring 70 others, prompting authorities to call in the Army and paramilitary forces for the challenging task of rescue and relief operations.

The accident occurred when the Millat Express train from Karachi to Sargodha derailed and fell on the opposite track and collided with Sir Syed Express headed from Rawalpindi to Karachi, a spokesperson of Pakistan Railways said.