The police helicopter and several units are responding to an incident in Rookley on Sunday morning (November 25).
Vehicles have parked up in the Sandy Lane area with Coastguard units also present.
It is unclear what they responding to but Hampshire Constabulary have been contacted for comment.
The helicopter is hovering near Blackwater Mill.
A witness at the scene says there is a large police, coastguard and fire service presence near the Blackwater Mill care home.
A witness at the scene claims a staff member heard calls for help at 6am.
A second member of the public also called police and a large search is underway according to a witness at the scene.
The Lee on Solent rescue helicopter has been searching for around two hours with a thermal imaging camera.
A spokesman for Blackwater Mill would like to reassure that all residents are safe and accounted for.
All emergency services have stood down from the search.
More as we get it…