The death toll from the collision between two passenger trains in Pakistan's Sindh province has increased to 62, a government official said on Tuesday.The death toll rose after rescue teams pulled out more bodies from the damaged compartments of the trains, Commissioner of Sukkur Shafiq Ahmed Mahesar told Xinhua news agency.He said that over 100 people sustained injuries in the accident and they are being treated at various hospitals of Pano Aqil, Ghotki and Mirpur Mathelo in the province, adding that the condition of at least 15 people is critical.The accident took place on Monday morning when a Sir Syed Express Train, which was en route from Lahore to Karachi, collided head on with the Sargodha-bound Millat Express train near Dharki city in Ghotki district.At least 13 compartments of the two trains were derailed and overturned, and seven to eight were completely destroyed in the accident, sources from the Pakistan Railways told Xinhua.Police sources in the area told Xinhua that special teams are still in the process of investigating the exact cause of the accident, however, they believe that multiple problems in the railway track and signal systems are possibly behind the accident.Meanwhile, the authorities have also cleared the railway track and train service which was halted since early Monday morning resumed operations.