Loyalists have expressed concern that the killing of a man in north Belfast could cause the loyalist feud in the west to spread to other parts of the city.
Mr David Greer (21) died after being shot in the chest at around 9.45 p.m. on Saturday. Police said they found his body in Mountcollyer Street in after responding to a phone call about disturbances in nearby Mileriver Street.
Although the RUC said it had yet to establish a motive for the killing, loyalists said it took place during a confrontation between members of the UDA, including Mr Greer, and the UVF.
Other units of both groups are involved in a feud on the Shankill Road in west Belfast. The feud has claimed the lives of three men and seen hundreds forced to leave their homes, but up to now it has been mostly limited to the Shankill.
Representatives of the political parties linked to the paramilitary groups blamed their opponents for starting the trouble.
Mr John White, the chairman of the Ulster Democratic Party, which has links to the UDA, said: "I thought we had seen the end of such killing. The UVF has killed a young man over nothing more than a fracas between the two organisations."
Mr White said the dispute between the two groups started on Friday night when a UDA supporter was attacked by a group of UVF men outside a pub.
The following night as many as 30 supporters of both groups confronted each other. During this, Mr White said, a car with UVF men inside pulled up, and one of the occupants shot Mr Greer.
Asked if he thought the intention had been to kill Mr Greer, Mr White said: "If you fire a gun at someone's chest it is meant to kill them," but admitted he did not know if the killing had been premeditated.
Mr Billy Hutchinson, the Progressive Unionist Party Assemblyman for north Belfast, said it was also his understanding that the dispute had begun on Friday but said it was UVF members who were attacked.
He said that on Saturday night two UVF men in a car were attacked and fired two shots in self-defence. He admitted they had killed Mr Greer but said: "It was not their intention".
The RUC said three cars were seen leaving the area immediately before Mr Greer was discovered.
Mr Hutchinson said he did not believe the killing was linked to the Shankill feud but feared the UFF's Shankill-based "C" company would use it as a pretext to import the feud into north Belfast.
UVF and UDA commanders in the area needed to "get a grip on the situation" and prevent this happening, he said.
Mr Davie Mahood, a UDP worker in north Belfast, also called for calm. "We don't want the Shankill feud extended into north Belfast, which has its own problems like sectarianism. We do not need an internecine feud," he said.