At least 119 train passengers were killed and more than 150 others injured as 14 passenger cars of and Indian express train derailed near the northern city of Kanpur in the early hours on Sunday.
The derailment occurred at around 3am when most passengers were asleep, near Pukhrayan, about 100km from Kanpur.
With the death toll set to rise, the derailment could become India’s worst rail tragedy since 2005, when a train was crushed by rocks and another plunged into a river – each killing more than 100 people.
Indian Railways spokesman Anil Saxena said, “We are yet to confirm the total casualties.”
Officials are investigating the possibility that the tragedy was caused by a rail fracture.
Poor track maintenance including lack of proper fittings and ballast on railway lines can cause tracks to crack.
Prime Minister Narendra Modi tweeted: “Anguished beyond words on loss of lives due to the derailing of Patna-Indore express. My thoughts are with the bereaved families.”
Railways Minister Suresh Prabhu has ordered an inquiry. Doctors and senior railway officials are at the scene.
Home minister Rajnath Singh also tweeted that he was deeply pained by the loss of lives.
Uttar Pradesh chief minister Akhilesh Yadav has directed the Kanpur director general of police to personally monitor the relief operations.
Northern Central Railways spokesman Vijay Kumar said buses had been used to help passengers to complete their journey.
The district administration and railway officials are carrying out rescue and relief operations, he said.
India’s creaking railway system is the world’s fourth largest. The federal government runs 11,000 trains a day, including 7,000 passenger trains that ferry more than 20 million people, but it has a poor safety record, with thousands of people dying in accidents every year, including in frequent train derailment and collisions.
Additional reporting by Reuters