At least four people were killed and dozens of others were injured when a passenger train derailed in eastern India late Wednesday, a government official said Thursday.

All 21 coaches of the North-East Express train, on its way to Assam state from New Delhi, derailed near Raghunathpur railroad station in Buxar district of Bihar state, Magistrate Anshul Agarwal said. Two of them overturned and rested on their sides.

Local residents rushed to the scene and helped passengers exit the derailed coaches. Ambulances later arrived and hospitals were alerted to receive injured passengers, police officer Deepak Kumar said.

D.K. Pathak, a railroad official who was on the train when it derailed, said most injuries occurred in one of the derailed coaches.

The cause of the derailment is being investigated.

Early reports said 70 passengers were injured. Agarwal said 31 of the injured were hospitalized. Others were able to go home after medical attention.

The rescue work was over by Thursday morning with all passengers accounted for, he added. Cranes and gas cutters were used to clear badly damaged railroad tracks.

"The train was coming at a normal speed but suddenly we heard a loud sound and saw a plume of smoke rising from the train. We rushed to see what happened. We saw that the train had derailed," the Press Trust of India cited Hari Pathak, a person living in the area, as saying.

In June, India had one of the country's deadliest rail crashes involving two passenger trains that killed more than 280 people and injured 900 others. A malfunction with the signal system was found to have caused the accident.

In 2016, a passenger train slid off the tracks between the cities of Indore and Patna, killing 146 people.

More than 12 million people ride 14,000 trains daily across India, traveling on 64,000 kilometers (40,000 miles) of track.