The head of the Prison Officers' Association (POA) has called on loyalists to call off their campaign against his members in Northern Ireland.
Mr Finlay Spratt made the plea after after an explosive device was left outside the house of a former officer in Co Down.
In the latest incident, damage was caused to the front door of a house in Donaghadee but no-one was hurt.
The device, made up of explosive powder in a container with nails attached, blew a hole in the front door of the property on the New Road.
The former officer had quit the prison service to look after his elderly parents and a sister who was left disabled by a hit-and-run car driver in Belfast.
It was the tenth attack this month on the homes of serving and former prison officers carried out by loyalists. Seven of the incidents have taken place in the last ten days.
They have been linked to violent protests at Maghaberry Prison near Lisburn, Co Antrim, where loyalists and republicans demanded segregation.
During the dispute, a group of dissident republicans held a "dirty protest" in their cells.
After a review of safety carried out last month, the Northern Ireland Office agreed to keep them apart, but additional security arrangements costing an estimated stg£7m have to be put in place and will not be completed until late this year.
Mr Spratt added: "These loyalists have been given separation at Maghaberry Prison. What else do they want? We will not work overtime to provide services to prisoners while these groups attack our homes."
Mr Peter Russell, Director General of the Northern Ireland Prison Service, also condemned the attacks.
"This is a disgrace. It is completely unacceptable and must stop," he said.
"Not only are these attacks on staff but they are attacks on their families."
Mr Russell added that putting the lives of women and children at risk to try and influence the way prison officers do their jobs should be condemned by all right-thinking people.
Meanwhile, a device was found at the home of a serving prison officer in Newtownards this morning.
The suspicious object found in the Ballyharry area of the town was taken away for further examination.
PA