The Ulster Defence Association has denied making a death threat against a Belfast-based journalist.
The National Union of Journalists (NUJ) said the warning had been issued by the UDA.
However, a spokesman for the Ulster Political Research Group in west Belfast, which advises the paramilitary organisation, said: "We consider anybody getting threatened to be absolutely not right and we are totally against any threats against any journalist."
The journalist's name has not been released but the NUJ has appealed to anyone with influence with the group to have the threat withdrawn.
Ulster Unionist leader Mike Nesbitt, a former television journalist, said the threat was "totally unacceptable and must be condemned unequivocally".
He called on the UDA leadership to state if the threat was officially sanctioned by the organisation and, if so, to withdraw it and to make clear its opposition to such menaces.
The NUJ insisted journalists would not be intimidated by threats and must be allowed to carry out their work without the threat of violence.
NUJ Irish Secretary Seamus Dooley said: "This represents the latest threat to this journalist and is part of a sinister campaign which must be condemned.
"A free press is the cornerstone of a democratic society and peace cannot be said to exist when journalists are faced with death threats."
The UDA is the largest of Northern Ireland's paramilitary groups.
It announced a ceasefire in October 1994 but in following years underwent a series of feuds and splits.
