Coastguard teams have joined the search for a walker who was reported missing yesterday.
The coastguard station in Lerwick confirmed that its rescue helicopter had been deployed to search the Central Mainland area.
Further teams are also assisting with the search on the ground.
Police Scotland first issued an appeal for Andrew Moorhouse yesterday (Thursday) after he was reported missing from his Lerwick home in the early hours of the morning.
Mr Moorhouse, 47, is said to be a keen walker and police believed he could have been trekking towards the north of the Mainland.
This morning, police issued a further appeal after receiving reports of a possible sighting of Mr Moorhouse, yesterday lunchtime near Whiteness.
He was wearing a dark green walking jacket and carrying a black rucksack.
The coastguard was asked to join the search at around 10am today.
Mr Moorhouse is described as being white, around 5ft 9ins, of stocky build with balding red hair and a beard.
Anyone who has information should call 101.