In his messages, sent on Saturday, Xi said he was shocked to learn of the accident, which caused major casualties.

On behalf of the Chinese government and people, Xi mourned the dead and expressed sincere sympathy to the bereaved families and injured people. He wished the injured a speedy recovery.

Premier Li Qiang also sent a message of condolence to Modi on Saturday.

The horrific accident happened on Friday when the Coromandel Express, traveling from Shalimar toward Chennai, derailed.

It collided with a freight train on the adjacent track, causing the rear cars of the Coromandel Express to veer off onto the third track.

The Yeswantpur-Howrah Superfast Express, coming from the opposite direction on another track, rammed into the derailed cars.

Indian Railway Minister Ashwini Vaishnaw said on Sunday that the tragic train accident in Odisha's Balasore district occurred due to a "change in electronic interlocking". An interlocking system refers to a safety mechanism that usually ensures the safe and efficient operation of train movements at railway junctions, stations and signaling points, the Hindustan Times reported.

Vaishnaw said restoration work was continuing at the site. "Our target is to finish the restoration work by Wednesday morning so that trains can start running on this track," he said.

Modi met with survivors of the accident on Saturday and said the government will leave no stone unturned to offer help and treat injured passengers. He added that it was a serious incident and instructions have been issued to probe it from every angle. Those found culpable "will be punished stringently", he added.