The only church designed by Charles Rennie Mackintosh has been broken into.
The unique Mackintosh Church is undergoing refurbishment
Thieves caused thousands of pounds worth of damage after they smashed a stained glass window at the building on Garscube Road, Glasgow.
The attack on the church, which draws tourists from around the world, happened at 2130 BST on Sunday.
The church is undergoing refurbishment and the Charles Rennie Mackintosh Society described the break-in as a "setback at an exciting time".
Stuart Robertson, chief executive of the society, said: "They've done extensive damage.
"I feel sick, it is a classic landmark building - unique."
The society, which is normally based at the church, believe the thieves climbed scaffolding and stole some property.
Strathclyde Police's Pc Stephen Cooke said: "This church has significant historical interest and attracts tourists from around the world.
"I would urge anyone with information to call me."
Commissioned in 1896, the Mackintosh Church finally opened to the public in 1899.