A dissident loyalist group - the Red Hand Defenders - has said it killed 19-year-old Catholic Ciarán Cummings in Antrim this morning.
A spokeswoman for Ulster Television told ireland.comit received a phone call from the group this afternoon and that it had passed the information to the RUC.
The spokeswoman could not confirm reports that the group killed the man because of the recent election of two Sinn Féin councillors in the area.
In 1999 the Red Hand Defenders - which is seen as a cover name for the UDA/LVF coalition - claimed responsibility for the killing of Portadown solicitor Ms Rosemary Nelson.
Ms Nelson was a legal representative of nationalist residents opposing the Drumcree Orange parade from proceeding down the Garvaghy Road in the town.
Mr Cummings was shot dead as he waited for a lift to work at the Greystone roundabout outside Antrim town at 7.30 a.m.
He was approached by two men on a black motorcycle and was shot several times. The motorcycle then left in the direction of the M2 motorway. The man died at the scene.
Assistant Chief Constable Alan McQuillan said "This was a very professional, well organised, well planned shooting. It was not random. They knew who they were going for."
The Minister for Foreign Affairs Mr Cowen called for calm adding: "the perpetrators have no mandate and no support from any decent member of society North or South. They seek a return to the despair and misery of the failed politics of the past. We are determined that they will not succeed".
Sinn Féin vice-president Pat Doherty accused former First Minister Mr David Trimble of increasing tensions in Northern Ireland by walking away from his post.
"Sinn Fein has been warning for some time that increasing levels of orchestrated loyalist violence would result in further loss of life. It is with great regret that our worst fears have come to pass in Antrim," he said.
"It is absolutely unbelievable that this political crisis should have been deepened by David Trimble on a focus around IRA weapons when the hard reality on the ground is that it is, on a daily basis, loyalist weapons and loyalist attacks that are affecting this process."
Friends of the victim said he had been one of a number of men who had been threatened by loyalists in Antrim town and claimed the killing could be linked to heightening tensions ahead of Sunday's banned march by Drumcree Orangemen.
A friend of the victim's family, Ms Mary Matthews said: "The whole family is devastated. They just cannot take it in.
"He was a normal 19-year-old with plenty of friends from both sides of the community.
"I don't know why anyone would want to kill him."
Antrim Sinn Féin councillor Mr Martin McManus said: "He was a Catholic and because of this silly Drumcree parade which is causing division in this country again this young man has lost his life."
Alliance Assembly member for South Antrim Mr David Ford accused the paramilitaries of trying to return the North to the dark days of the 1970s and 1980s.
The RUC is appealing to anyone in the area at the time of the killing to contact them.
additional reporting PA
