The Advanced Light Helicopter (ALH) lost contact soon after its take off from Sagalee at around 3.50 pm before the rescue, Defence PRO Lt Col Sambit Ghosh said.
The chopper was evacuating people, stranded at Sagalee due to landslides, triggered by rains.
Sources at the chief minister’s office here said Chief Minister Pema Khandu was monitoring the situation.
Directives have been issued to the administration and the police to extend all possible help in the search and rescue operation.
The villagers have also asked to help the administration in locating the missing chopper, the sources said.