BALASORE (India): The cause of India’s deadliest train disaster in decades was linked to the signal system, the railway minister said Sunday, as families scoured hospitals and morgues for missing relatives with deaths expected to top 288.

Mounds of debris were piled high at the site of Friday night’s crash near Balasore in the eastern state of Odisha, as workers started to clear the smashed carriages and the blood-stained wreckage where hundreds were also wounded.

Hospitals have been overwhelmed by the number of casualties.

“We have identified the cause of the accident and the people responsible for it,” India’s Railway Minister Ashwini Vaishnaw told news agency ANI, but said it was “not appropriate” to give details before a final investigation report.

There was confusion about the exact sequence of events but reports cited railway officials saying a signalling error had sent the Coromandal Express running south from Kolkata to Chennai onto a side track.

It slammed into a freight train and the wreckage derailed an express running north from India’s tech hub Bengaluru to Kolkata that was also passing the site. Odisha state’s chief secretary Pradeep Jena confirmed that about 900 injured people had been hospitalised.

Vaishnaw said the “change that occurred during electronic interlocking, the accident happened due to that”, a technical term referring to a complex signal system designed to stop trains colliding by arranging their movement on the tracks.

“Whoever did it, and how it happened, will be found out after proper investigation,” he added.

Prime Minister Narendra Modi visited the crash site and injured passengers being treated in hospital on Saturday and said “no one responsible” would be spared.