Security at Aberdeen Art Gallery was stepped up before it closed for re-development for fear of theft, it has emerged.
Safety procedures were reviewed and steps taken to protect its collections following a spate of break-ins at museums around the UK, Ireland and Europe in recent years.
The item of choice for thieves was mainly Rhino horns which are highly valued in Asian medicine in powered form and can sell for tens of thousands of pounds.
The information about Aberdeen Art Gallery, which will reopen in 2017, was released after pressure group The Taxpayers Alliance asked the local authority how many pieces of artwork it owned, display arrangements and its estimated total value.
The council, which is spending £30million to improve the facility, Cowdray Hall and Memorial Court, revealed it held 12,374 pieces of art and 789 were on display prior to the gallery closing.
Information compliance officer Jacqueline Gillanders said releasing information may allow would-be thieves to “locate accurately the most valuable works in the collection” and put staff at risk.
She added that there had been several incidents of theft from museums recently, both of works on display and in storage.
“These thefts relate mainly to rhinoceros horn, which may be a natural history specimen or a decoratively carved object,” said Ms Gillanders.
“However this increase in art-related theft has led Aberdeen Art Gallery and Museums to review its security procedures and take additional steps to protect its collections.
“These and other robberies are carefully pre-planned and it is our view that releasing both valuations and locations of artworks in our collections would assist those intent on criminal actions.”
Ms Gillanders said the city council considered that financial valuation of works of art, which can fluctuate, was inherently difficult and did not add to the appreciation of the collection.
The 12,374 items have been individually packed, catalogued for tracking, and either relocated to a secure storage facility in Mastrick or out to exhibition spaces across Scotland.
Locations include Aberdeen Maritime Museum, Drum Castle near Drumoak in Aberdeenshire and galleries in Berkshire, Eastbourne and London.