Hyderabad,  Another 'fire' in underground hydroelectric station at Telangana's Srisailam created panic on Wednesday but a top official later clarified that it was a 'mock drill' to check the preparedness of the employees in the event of an accident.

Employees at the Telangana State Generation Corporation (TS Genco) plant at Srisailam left bank canal in Nagarkurnool district ran out in fear with 'fire' breaking in one of the units where repair works going on after last month's fire.

Coming close on the heels of the August 20 fire accident which claimed the lives of nine employees, the fire, accompanied by explosions, triggered chaos among the workers. All employees present at the scene came out safely.

They heaved a sigh of relief after it was announced that it was only a mock drill to check their preparedness. TS Genco and Telangana State Transmission Corporation (TS Transco) Chairman and Managing Director Prabhakar Rao said it was a mock drill.

The mock drill was kept a secret with only Prabhakar Rao and another senior official aware of it. They said it was conducted to check the emergency response system.

This was done in the wake of reports that nine employees were trapped in the August 20 fire as they were not properly guided about the exit from the tunnel in the event of a fire.

A short circuit is believed to have caused last month's fire in the underground power house. Of the 30 employees present at the scene, 15 could escape to safety while six were rescued.

Srisailam dam is located across Krishna river which serves as the border between Telangana and Andhra Pradesh.

Telangana Chief Minister K. Chandrashekhar Rao had already ordered a probe by the CID into the fire accident.

Additional Director General of Police, CID, Govind Singh is heading the probe.