At least 51 passengers have died after two express trains collided in southern Pakistan.
More than 100 were injured, and rescuers and villagers worked throughout the day to pull survivors and the dead from the crumpled cars.
Cries for help pierced the night as passengers climbed out of overturned or crushed rail cars, and local people rushed to the scene in the district of Ghotki, in the southern province of Sindh.
At around 3.30am, the Millat Express derailed and the Sir Syed Express train hit it soon afterwards. It was not immediately clear what caused the derailment and the subsequent collision.
Later in the day, heavy machinery arrived to cut open some cars, in the hopes of rescuing several people still believed to be trapped. The military deployed troops and helicopters to assist.
“The challenge for us is to quickly rescue those passengers who are still trapped in the wreckage,” said Umar Tufail, a police chief in the district.
Officials said more than 100 passengers were injured, and those with critical injuries would be brought by helicopter to a nearby city’s hospital. According to railway officials, about 1,100 passengers were on board the two trains.
The death toll has risen steadily through the day, and the chances of finding survivors were diminishing, said Rizwan Nazir, a district administration official.
Authorities brought in lights so rescuers could work through the night. Relatives of some of the missing passengers waited nearby.
Passengers with critical injuries were brought by helicopter to a nearby hospital.
Azam Swati, minister for railways, said engineers and experts were trying to determine what caused the collision. He said all aspects will be examined, including the possibility of sabotage.
“We are not sure about the cause of the train accident at this stage,” he said.
Habibur Rehman Gilani, chairman of Pakistan Railways, told Pakistan’s Geo News TV that the segment of the railway tracks where the crash took place was old and needed replacing. He did not elaborate.
Aijaz Ahmed, the driver of the train that collided with the derailed train, told Pakistan’s Geo News TV that on seeing the derailed train cars, he tried his best to avoid the accident by braking but failed.
Pakistan’s prime minister expressed his deep sorrow over the tragedy.
Imran Khan said on Twitter that he had asked the railway minister to supervise the rescue work and also ordered a probe into the crash.
Boris Johnson spoke to Khan in the wake of the crash. A Downing Street spokesperson said Johnson "expressed his condolences following the tragic loss of life in the train crash in Sindh".
Train accidents are common in Pakistan, where successive governments have paid little attention to improving the poorly maintained signal system and ageing tracks.
In 1990, a packed passenger ploughed into a standing freight train in southern Pakistan, killing 210 people in the worst rail disaster in Pakistan’s history.