At least 119 people are dead and more than 150 injured after an Indian express train derailed in northern state of Uttar Pradesh, with the toll set to rise amid a scramble to locate survivors.
Police officials said people were still missing as authorities tried to ascertain what caused 14 carriages of the train travelling between the northeastern city of Patna and the central city of Indore to suddenly roll off the tracks in Pukhrayan, 65 km south of Kanpur city on Sunday.
Authorities said they were checking the condition of the tracks but would need to look further before concluding the cause of the derailment, India's deadliest rail tragedy since more than 140 died in a 2010 collision in West Bengal.
Kanpur district magistrate Kaushal Raj Sharma told Reuters that 119 people were confirmed dead, while 78 of the injured remained in hospital.
With rescue teams still looking for victims amid the wreckage, the toll from the derailment could rise to become India's worst rail tragedy in this century.
India's creaking railway system is the world's fourth largest. It runs 11,000 trains a day, including 7000 passenger trains carrying more than 20 million people.
But it has a poor safety record, with thousands of people dying in accidents every year.
Indian Prime Minister Narendra Modi, who started out selling tea outside a train station, has promised to modernise India's railways and build high-speed lines befitting Asia's third-largest economy.
His government has pledged to replace old tracks and upgrade security infrastructure but little progress has been made so far.
By some analyst estimates, the railways need 20 trillion rupees (NZ$418 billion) of investment by 2020, and India is turning to partnerships with private companies and seeking loans from other countries to upgrade its network.
Last year, Japan agreed to provide US$12 billion in soft loans to build India's first bullet train.
On Sunday, Modi took to Twitter to express his condolences.
"Anguished beyond words on the loss of lives due to the derailing of the Patna-Indore express. My thoughts are with the bereaved families," Modi said.