NEW DELHI, Dec. 23 (Xinhua) -- A passenger train derailed in the southern Indian state of Telangana Saturday, railway officials said.

There has been no report of any casualty in the incident so far, but the accident has affected railway operation in the region.

"The mishap took place when a coach of Tirupati-Nizamabad Rayalaseema Express went off the tracks between Uppalavai and Sirnapalli stations," an Indian Railway official said.

"The accident has severely disrupted rail traffic in the region. We are trying our best to restore rail movement," he said.

A probe has been ordered into the incident, the official added.

The state-owned Indian Railways is one of the world's largest train networks, criss-crossing the country from north to south and ferrying around 23 million passengers daily.

But its safety record is very poor mainly due to the colonial-era ailing railways.