Train was travelling from Patna to Indore when it derailed on Sunday morning, throwing several carriages off the tracks.
At least 90 people were killed and more than 100 injured when a train derailed in northern Uttar Pradesh, India’s biggest state, police said.
The train was travelling between the northeastern city of Patna and the central city of Indore on Sunday when the incident happened, throwing several carriages off the track, according to railway officials.
"As we know a major accident has happened in which the entire train turned turtle. The death toll has unfortunately increased and it is 91 now," Daljit Singh Chawdhary, the additional police director general of Uttar Pradesh state, told AFP news agency.
"A lot of teams are currently there including local police, doctors and members of the National Disaster Response Force. The rescue operations are on."
All local hospitals had been placed on alert and around 30 ambulances had been deployed to transport the injured.
India’s Home Minister Rajnath Singh said the Patna-Indore Express train had derailed near Kanpur, in northern India and that the National Disaster Response Force was overseeing the rescue efforts.
"Dozens of passengers were injured in the derailment. We don’t know what led to the disaster," said a senior railway official R K Chandra in Kanpur.
Al Jazeera’s Faiz Jamil, reporting from the capital Delhi, said the crash happened at around 3am local time.
"It happened about 450km southeast of Delhi and the local rescue teams have now been joined by the state and national teams. The railway officials have said they will be looking into the cause of the derailment," he said.
TV footage showed rescue workers trying to cut through severely mangled coaches with suitcases and other luggage strewn around.
Witnesses spoke of being woken up by a huge bang and being thrown around.
"We woke up to a great thud this morning. It was pitch dark and the noise was deafening," a passenger told reporters as he waited with his family at the accident site.
"I am lucky to be alive and safe. But it was a near-death experience for us."
Suresh Prabhu, India’s railways minister, said in a tweet that the government would immediately investigate the causes of the derailment and promised accountability with the "strictest possible action".
India’s creaking railway system is the world’s fourth largest, ferrying more than 20 million people each day, but it has a poor safety record, with thousands of people dying in accidents every year.
The nation suffers frequent train derailments, sometimes with tragic consequences, including another train accident in Uttar Pradesh in March last year that killed 39 people and injured 150.