New Delhi: Indian Air Force (IAF) helicopters were put on standby for evacuation of affected people in Himachal Pradesh in the event of flash floods as China informed India of the "potentially serious" situation with water flowing over a dam in Tibet.

"The dam has not burst. The water is discharging. But naturally the condition is not stable," External affairs Ministry spokesman Navtej Sarna told reporters in New Delhi.

He said the Chinese side has informed New Delhi that water from the artificial dam has been flowing over it. "They (Chinese) pointed to the instability of the artificial dam and the potentially serious situation that prevails."

On reports that there has been an explosion at the dam, he said there was no confirmation "either way".

Detailing steps taken by the Government, he said IAF helicopters have been put on standby for any evacuation of people and for ferrying supplies as may be required.

A chain of wireless sets have been set up along the villages on the banks of the Pareechu river, Spiti downstream Sutlej downstream of Khad. These would help pass on warning signals of rising water levels.

"All the villages have been sensitised in advance and they have been advised to select places to which people can evacuate in case of flash floods and have been advised to move to the designated places," he said.