Two loyal order banners and a historic portrait of King William have been stolen during a break-in at a Londonderry Orange Hall.
Considerable damage was also caused during the Friday night attack on Fawney Orange Hall, which lies on the outskirts of the city.
During the incident two plaques commemorating the opening of the building were daubed with republican graffiti.
An Orange Order spokesman said: “The perpetrators also ransacked cupboards in the premises, before throwing the contents across the floor of the hall.
“An initial assessment of the damage caused and subsequent theft has estimated the cost of the break-in could be as much as £10,000.”
Deputy Grand Master of the City of Londonderry Grand Lodge, Maurice Devenney, condemned those behind the “sectarian” attack on the Orange property.
He said: “The perpetrators cut through a fence at the rear of the hall, removed roof tiles and busted a large hole in the ceiling to gain entry.
“This was undoubtedly a pre-planned and despicable hate crime on the Protestant community in Londonderry. Not content to engage in wanton vandalism, those who carried out this wicked deed also took it upon themselves to steal a number of items, including a portrait of King William and two banners, which are of great historic, cultural and financial value to the lodges concerned.
“Even at this stage, I would appeal to these people to examine their consciences, do the honourable thing and return the items in their original state immediately.”
Following the attack, Mr Devenney has requested that the PSNI increase their presence around rural halls in the Londonderry area. He also appealed for any witnesses to come forward with any information to police as a matter of urgency.
The Orange hall is used by the membership of Fawney Fort LOL 248 and a local Royal Black Preceptory. During the Troubles, the building was destroyed on two occasions in separate arson attacks in 1975 and 1986 respectively.
The Orange Order spokesman said Friday nights incident at Fawney “is the fifteenth reported attack on Orange property so far this year”.
Earlier this week, Clifton Street Orange Hall in north Belfast was targeted in a paint bomb attack.
A PSNI spokesman who confirmed they are investigating the incident said “entry was gained to the Fawney Road premises via the roof and a number of banners and a painting stolen”.
“Sectarian graffiti was also scratched onto two brass plaques in the Foyer.”
Police are appealing for anyone with information to get in contact with them on 0845 600 8000.
Or if someone would prefer to provide information without giving their name they can call the Crimestoppers charity on 0800 555 111.