Two trains derailed in India in the eastern state of Odisha on Friday, government officials said, killing as many as 120 people and injuring hundreds more in an accident that shook the country.

Sudhanshu Sarangi, the director general of the fire department in Odisha, told Reuters that 120 bodies had been recovered. Odisha’s chief secretary, Pradeep Jena, said on Twitter that another 850 people had been injured.

Indian news reports described harrowing scenes as teams of rescue workers with dogs and cutting equipment labored frantically to free the injured who were trapped in the train wreckage.

Amitabh Sharma, a railroad ministry spokesman, was quoted by The Times of India as saying that 10 to 12 coaches of one train had derailed and that some of the debris then landed on a nearby track, where it was hit by another train.

Video footage of the scene of the crash showed stunned onlookers, and Indian news reports said more than 50 ambulances had arrived to the area, along with teams of doctors to tend to the injured.

Ashok Samal, a shopkeeper, told The Hindustan Times that he was ending his day near the railway track in his village of Bahanaga on Friday when he heard a deafening noise, ran to the track on the main line between Kolkata and Chennai, and saw a pile of mangled train cars.

“There were loud shrieks and blood all over,” he told the newspaper, adding that he saw people trapped under coaches and people wailing for help.

Ashwini Vaishnaw, the minister of railways, said on Twitter that the National Disaster Response Force had been mobilized, along with rescue workers from the air force. Dozens of trains were canceled.

Prime Minister Narendra Modi offered his condolences on Twitter. “Distressed by the train accident in Odisha,” he wrote. “In this hour of grief, my thoughts are with the bereaved families. May the injured recover soon.”

Mr. Vaishnaw told the Indian news agency ANI that he had ordered an investigation to determine the cause of the crash.

Indian news reports said that as news of the crash spread, along with reports of mounting casualties, desperate relatives went to Howrah Station in West Bengal, where one of the trains had been heading, eager to determine the status of their loved ones.

At Howrah, one man, Sapan Chowdhury, told The Indian Express he was relieved to learn that his 23-year-old daughter was alive, though she had been injured by glass shards.

India’s trains transport more than 13 million people a day, according to Indian Railways, but the system has been buffeted by years of neglect. In 2014, there were more than 27,000 train-related deaths, according to the country’s National Crime Records Bureau. In 2012, a committee appointed to review the safety of the rail network cited “a grim picture of inadequate performance largely due to poor infrastructure and resources.”

It recommended a host of urgent measures, including upgrading track, repairing bridges, eliminating level crossings and replacing old coaches with safer ones that better protect passengers in case of an accident.

Passenger safety, or the lack of it, has come under scrutiny in India in recent years. In 2016, more than 140 passengers died in the derailment of passenger coaches near the city of Kanpur.