Belfast city council staff have been intimidated from working in north Belfast after being threatened by loyalist paramilitaries.
Housing executive officials confirmed threats were made in an attempt to force the authority to allocate properties in the Ballysillan estate. Council workers left the area, and staff at a district office in the city also halted work.
Political representatives have been urged to intervene in an attempt to have the threat lifted. Paddy McIntyre, chief executive of the Northern Ireland Housing Executive, said he did not expect anyone to work amid fears for their safety.
"We need assurances that our staff can continue to go about their work safely and we are talking to public representatives as a matter of urgency."
The alert followed a telephone call on Thursday from an ex- Ulster Defence Association prisoners' association in the staunchly Protestant Ballysillan district. The caller said a message had been received from an unknown source that no more vacant properties were to be let out in the area or tenancy repairs carried out.
The warning came a day after the Executive refused demands from a Ballysillan resident to give an empty house next door to her friend.
A contractor and maintenance officer were also confronted by a mob who ordered them out as tensions rose.
Around 40 employees at an Executive office, which deals with Ballysillan, staged a walk-out as soon as they learned of the threats.