New Delhi, India (CNN) -- Six passengers were killed and 20 injured when a train derailed in northwestern India early Saturday, officials said.

The New Delhi-bound train derailed at 1:30 a.m. local time near Jaipur in Rajasthan state, said K.L. Enkhia, railway spokesman.

At least 15 cars came off the tracks, he said, adding that train traffic on the route has been diverted.

Passengers were taken to their destinations by bus, Enkhia said. The cause of the derailment is under investigation.

India's massive railway network crisscrossing the country has been marred by a poor safety record. The country had 117 train accidents in 2008-09, according to figures released by the railway in July. Out of the total, 80 were blamed on staff failure.

In 2007-08, India recorded 194 train crashes.