Police have arrested two men in connection with the killing of Catholic postman Mr Daniel McColgan (20) early on Saturday. The father of one was shot dead as he arrived for work at 4.45 a.m. at a postal sorting office in the loyalist Rathcoole estate on the outskirts of north Belfast.
The killing was admtted by the loyalist paramilitary group the Red Hand Defenders, a cover name used by the Ulster Defence Force.
Police confirmed they were in no doubt that the UDA was responsible.
In its statement admitting responsibility for the killing, the Red Hand Defenders said all Catholic postal workers were now considered "legitimate targets".
On Friday night it issued a similar threat against teachers and Catholic workers at Catholic schools in Belfast.
Mr McColgan, from Longlands Court in Newtownabbey, Co Antrim, was getting out of his car at the Royal Mail office at Barna Square when two gunmen approached him.
It is thought t they fired several shots, hitting him a number of times. A green Renault 14 Energy car, believed to have been used by the gunmen, was later found burnt out a short distance away.
In a statement, Mr McColgan's partner, Ms Lindsey Milliken, with whom he had a 13-month-old daughter, appealed for no retaliation. Ms Milliken said her and Mr Colgan's families were "deeply distressed" and could only ask themselves: "Why Daniel?"
In a joint statement last night, the First and Deputy First Ministers, Mr David Trimble and Mr Mark Durkan, called for the lifting of the threats against Catholic teachers and postal workers. They also insisted that all attacks against public sector workers, such as ambulance staff, firefighters, bus and train drivers, had to stop.
"Workers should be able to earn a living free from any form of attack or intimidation. Schools should be a haven for children, a place where they can learn and understand more about the importance of tolerance and respect for others.
Attacks on pupils travelling to and from school, which have been witnessed from both loyalist and republican communities, should also cease immediately," they added.
The detective in charge of the murder investigation, Supt Roy Suitter, said Mr McColgan was targeted for the simple reason that he was a Catholic working on a loyalist estate.
While the UDA later distanced itself from the threats, the PSNI assistant chief constable for Belfast, Mr Alan McQuillan, said his officers would not take any chances. "We will have an extensive security operation in place to protect both schools and postal workers in north Belfast," he told The Irish Times.
Postal workers walked out in protest at the killing on Saturday, and there were no collections or deliveries yesterday. Nor will there be any today as a mark of respect. The move is supported by Royal Mail, which called on all those with influence in the community to do everything in their power to get the threat against Catholic postal workers lifted.
Meanwhile, the North's Education Minister, Mr Martin McGuinness, is to meet representatives from the education sector this morning to discuss the loyalist threat against school staff.