A crash involving three trains in India’s eastern Odisha state, has left at least 261 people killed and 1,000 injured.

One passenger train derailed on to the adjacent track and was struck by an incoming train on Friday, also hitting a nearby stationary freight train.

A massive recovery operation is under way, after hundreds of emergency workers searched the wreckage.

The cause of India’s worst train crash in over 20 years is not yet clear.

Officials say several carriages from the Coromandel Express, travelling between Kolkata (formerly Calcutta) and Chennai (formerly Madras), derailed at about 19:00 (13:30 GMT) in Balasore district after hitting a stationary goods train. Several of its coaches ended up on the opposite track.

Another train travelling in the opposite direction – the Howrah Superfast Express travelling from Yesvantpur to Howrah – then hit the overturned carriages.

“The force with which the trains collided has resulted in several coaches being crushed and mangled,” Atul Karwal, chief of the National Disaster Response Force (NDRF) told ANI news agency.

More than 200 ambulances and hundreds of doctors, nurses and rescue personnel were sent to the scene, the state’s chief secretary Pradeep Jena said.

Sudhanshu Sarangi, director general of Odisha Fire Services, had earlier said 288 had died.

All trapped and injured passengers have been rescued. It is not clear how serious the injuries of those taken to hospitals were.

Work to restore the site of the crash begun, India’s South Eastern Railway company said on Saturday.

Prime Minister Narendra Modi visited the site of the accident on Saturday afternoon, joining Railway Minister Ashwini Vaishnaw at the scene.

An investigation into the cause of the crash has been launched, although Education Minister Dharmendra Pradhan has blamed “technical reasons”.

Survivors and eyewitnesses have described chaotic scenes and the heroic efforts of people from nearby villages to save trapped passengers.

Mukesh Pandit, who was trapped for half an hour before being rescued, told the BBC he heard a “thunderous sound” shortly before the carriage overturned.

“Four passengers who were travelling from my village have survived, but a lot of people are injured or still missing. A lot of people died in the coach I was travelling in,” he added.