At least four people were killed and about 80 injured as an express train derailed in the northeastern Indian state of Bihar on Wednesday, a local official told Reuters.

Twenty-one coaches of the North-East Express train, which runs from Delhi to Assam, derailed at the Raghunathpur railway station in Bihar's Buxar district around 1605 GMT on Wednesday, Tarun Prakash, general manager of East Central Railway, said.

Some of the 80 injured were sent to Patna, the capital of Bihar, the official said.

The cause of the derailment was not immediately known.

Several other passenger and goods trains were diverted due to the accident, media reports said.

Prakash, the railway manager, said rescue operations were ongoing, but Minister of Railways Ashwini Vaishnaw said on social media network X that the train's evacuation and rescue were complete.

"All coaches checked. Passengers will be shifted to a special train soon for onward journey," he posted.

In June, India experienced its worst train crash in two decades in Odisha, which resulted in the death of at least 288 people.