In one of the worst railway tragedies in India in recent years, at least 91 people were killed and more than 150 others injured after an express train derailed in the northern state of Uttar Pradesh early Sunday morning. "The mishap took place around 3:30 a.m. (local time) near Pukhrayan, close to the town of Kanpur in Uttar Pradesh. Some 14 coaches of the Indore-Patna Express ran off the tracks at a time when most of the passengers were asleep," a senior railway official said. While 91 bodies have been pulled out of mangled coaches so far, those injured were admitted to hospitals across Kanpur, where the conditions of many are said to be serious, the official said, on condition of anonymity. The Indore-Patna Express, which is the only bi-weekly train that runs from the central state of Madhya Pradesh to the eastern state of Bihar's capital Patna, was on its way to Patna when the fatal accident took place. Local TV channels showed footage of mangled coaches piling up against each other on railway tracks and rescuers trying to cut through the windows using gas-cutters to get through to rescue trapped passengers, including the elderly and women. Reports also said that Indian Army and Indian Air Force doctors have been pressed into service to comfort and treat the injured passengers at the accident site, while private buses are being used to ferry passengers and help them complete their journey. 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. Luckily I survived," Sunil Rai, a passenger, was quoted as saying. Indian Prime Minister Narendra Modi has condoled the deaths in the accident and said he spoke to Railway Minister Suresh Prabhu, who was monitoring the situation closely. "Anguished beyond words on the loss of lives due to the derailing of the Patna-Indore express. My thoughts are with the bereaved families," he tweeted. On his own Twitter account, Prabhu warned that "strictest possible action will be taken against those who could be responsible for accident." Another senior Indian Railways official Vijay Kumar told the media in Delhi that the cause of the accident was not known immediately, but a probe has been ordered. "An investigation will be carried out soon to ascertain the exact reason for the mishap," he said. The Indian Railways has also announced a compensation of 350,000 rupees (7,500 U.S. dollars) to the families of those killed and 50,000 rupees (900 U.S. dollars) to those seriously injured in the train accident. The mishap has also severely affected movement of trains in the region as Kanpur town is a major railway junction and hundreds of trains pass through it every day. Indian Railways is one of the world's largest railway networks, criss-crossing the country from north to south and carrying over 23 million passengers daily. However, train accidents are common in India, where much of the railway equipment is out of date. Some six major train accidents have taken place in India till date this year, though this is the one that recorded the highest number of casualties.