Two trains derailed in India on Saturday, killing at least four passengers, including two British tourists, officials said.

Three coaches of a special tourist train went off the tracks near the northern hill town of Kalka, in Himachal Pradesh state.

The train was rounding a curve when the coaches derailed, said Neeraj Sharma, a railway official.

Two women, both British tourists, died instantly in the accident. Five other passengers were injured, Sharma said.

No other details were immediately available.

Suresh Prabhu, India's railway minister, ordered an investigation into the accident. The train, known as "a toy train," is a tourist attraction, with only five coaches, and does a scenic route to the mountain resort town of Shimla.

Earlier Saturday, nine coaches of a train derailed in southern India, killing at least two people and leaving several injured.

Police and rescuers helped pull out scores of passengers from the coaches, which fell onto their side near Gulbarga in Karnataka state after the train derailed at about 2:15 a.m., Indian Railway spokesman Anil Saksena said.

The injured were taken to hospitals in Gulbarga, about 600 kilometers (370 miles) north of India's technology hub of Bangalore.

The cause of the derailment was not immediately known.

India operates one of the world's largest railroad networks, with about 23 million passengers traveling by train every day.

However, safety standards on the massive state-run railway network have been an ongoing concern amid a spate of accidents.

Last month, two passenger trains derailed over a bridge in central India while crossing a track that was flooded by heavy monsoon rains, killing at least 24 people.