Members of Estonia's branch of the International Council on Monuments and Sites (ICOMOS) have called plans to create a 100-seat restaurant inside the ruins of Tartu Cathedral "unacceptable".
Earlier this month it was announced the owners of top-rated Tallinn restaurant Noa want to open a 100-seat restaurant in the ruins of Tartu's 13th cathedral, which belongs to the University of Tartu.
Designs by architecture firm KOKO suggest a glass pavilion could be built at the location.
The City of Tartu backs the idea and plans to host guests at the venue when it becomes the EU's 2024 capital of culture.
But heritage activists are against the idea saying it will spoil the site's "integrity and authenticity".
"The restaurant does not add value but exploits and destroys the cultural value of the ruins of the cathedral. Building a restaurant in the ruins of the cathedral closes public space and will not allow public activities and events to continue there," head of ICOMOS Estonia, Ave Paulus, wrote in a public appeal to the University of Tartu.
"Such vigorous exploitation of a cultural monument carried out for private and commercial interests and closing public space on Toomemägi is unacceptable," she added.
Paulus said the ruins must be preserved "completely and authentically" as a part of the city's public space for future generations.
Editor: Helen Wright