Postal workers in Derry meet this morning to discuss the latest threats issued to staff by loyalists.
Staff at the Great James's Street sorting depot meet at 5 a.m. to co-ordinate a response to an incident in which a bullet was allegedly sent to the home of a Catholic employee, the latest in a series of scares this year in the city and following the shooting of Danny McColgan by the UDA near Belfast in January.
Services have been curtailed over the weekend due to fears about security.
These fears have escalated following the murder of David Caldwell in the city last week. Postal workers see themselves as soft targets like the construction worker blown up at the Territorial Army base in the city.
The workers' union has said it is keen for service to be returned to normal but insisted the security of its members took priority.
The Royal Mail has expressed concern about the continuation of normal "essential service" but stressed that worker safety was of prime importance.
Postal services in Derry were last disrupted in February following delivery of a threatening letter naming 11 staff, both Catholic and Protestant, warning them against working in the largely Protestant Waterside area of the city.
Deliveries were also disrupted earlier that month when a Catholic worker was threatened.
Catholic postmen and other public sector workers were threatened by the UDA in north Belfast following the McColgan murder in January.