(AFP) - At least 288 people were killed and hundreds more injured in a horrific three-train collision in India, officials said Saturday, the country's deadliest rail accident in more than 20 years.

Wreckage debris was piled high at the crash site near Balasore, in the eastern state of Odisha, where some carriages had been tossed far from the tracks and others flipped over entirely.

Smashed train compartments were torn open in the impact late on Friday, leaving blood-stained holes in their sides.

Researcher Anubhav Das was in the last carriage of one of the trains when he heard "screeching, horrifying sounds coming from a distance".

His coach stayed upright and he jumped out unhurt after it ground to a halt.

"I saw bloodied scenes, mangled bodies and one man with a severed arm being desperately helped by his injured son," the 27-year-old told AFP.

"I lost count of the bodies before leaving the site. Now I feel almost guilty."

The disaster began when an express train running north from India's tech hub Bengaluru to Kolkata derailed, falling onto the adjacent southbound track.

Minutes later, the Coromandal Express heading from Kolkata to Chennai smashed into the wreckage, some of its coaches also colliding with a goods train parked alongside.

Residents nearby rushed to help the victims even before emergency services arrived.

"There were severed arms, legs, and even some partially severed heads -- while the unluckier ones died in pain, too much pain," said Hiranmay Rath.

Over the next few hours the 20-year-old saw "more death and grief" than he could have "ever imagined", he told AFP.

The rescue effort was declared over on Saturday evening after emergency personnel had combed the mangled wreckage for survivors and laid scores of bodies out under white sheets beside the tracks.

"All the dead bodies and injured passengers have been removed from the accident site," said an official from the Balasore emergency control room.

Sudhanshu Sarangi, director general of Odisha Fire Services, said the death toll stood at 288 but was expected to go higher, potentially approaching 380.

Prime Minister Narendra Modi visited the crash site and injured passengers being treated in hospital and said "no one responsible" for the train crash would be spared.

"It's a sad moment," he told state broadcaster Doordarshan. "I pray that we get out of this sad moment as soon as possible."

- Third worst ever -

India has one of the world's largest rail networks and has seen several disasters over the years, the worst of them in 1981 when a train derailed while crossing a bridge in Bihar and plunged into the river below, killing between 800 and 1,000 people.

Friday's crash ranks as its third-worst, and the deadliest since 1995, when two express trains collided in Firozabad, near Agra, killing more than 300 people.

Odisha state's chief secretary Pradeep Jena confirmed that about 900 injured people had been hospitalised.

Rescue teams including from the National Disaster Response Force and the military were deployed, while the railways ministry announced an investigation.

Authorities said every hospital between the crash site and the state capital Bhubaneswar around 200 kilometres (125 miles) away was receiving victims, with 200 ambulances -- and even buses -- deployed to transport them.

At Bhadrak District Hospital, bloodied and shocked survivors were receiving treatment in crowded wards.

The disaster comes despite new investments and upgrades in technology that have significantly improved railway safety in recent years.

Condolences came in from around the world.

Pope Francis said he was "deeply saddened" by the "immense loss of life" and offered prayers for the "many injured".

French President Emmanuel Macron sent his condolences to India's president and prime minister, saying in a tweet that his "thoughts are with the families of the victims".

© Agence France-Presse