At least 233 people have been killed after three trains were involved in a crash in eastern India.

Hundreds of others were injured when a passenger train derailed and collided with another passenger service that then hit a goods train in Odisha's Balasore district on Friday evening.

The cause of the crash is being investigated.

Odisha's chief secretary, Pradeep Jena, said rescue efforts are in "full swing" and nearly 500 police officers and rescue workers with 75 ambulances and buses responded to the accident.

Rescuers were attempting to free 200 people feared trapped in the derailed carriages, said D B Shinde, the Balasore district administrator in Odisha state.

The Coromandel Express, which runs from Kolkata to Chennai, derailed after the collision and fell on the opposite track.

Speaking from India, Sky reporter Neville Lazarus said the crash took place at around 7.30pm local time and that all hospitals in the Balasore district have been put on high alert.

He said the trains involved in the crash run along important routes which are "one of the main artery tracks" of the eastern side of the country's network.

PM Modi 'distressed'

India's Prime Minister Narendra Modi said he is "distressed" by the accident and said rescue operations are under way at the site.

Photos from the scene show people trying to escape from a toppled carriage.

A railroad ministry spokesperson, Amitabh Sharma, said 10 to 12 carriages of one train derailed, and debris fell on to a nearby track.

Passenger Vandana Kaleda told the New Delhi Television news channel that she "found people falling on each other" as her carriage shook violently and veered off the tracks. She said she was lucky to survive.

More than 12 million people ride 14,000 trains across India every day, travelling on 40,000 miles of track.

Despite government efforts to improve rail safety, several hundred accidents occur every year on India's railways, the largest train network under one management in the world.

Most train accidents are blamed on human error or outdated signalling equipment.