The Progressive Unionist Party has been urged to "firmly disown" loyalist paramilitaries, the Ulster Volunteer Force.
Craig McCausland died after being shot in Dhu Varren Park
Alban Maginness, SDLP, made the call as the funeral took place of Craig McCausland, 20, the second person to die in the UVF/LVF feud.
His family blames the UVF. He died after being shot in Dhu Varren Park, north Belfast, early on 11 July.
His family deny he had any involvement with the Loyalist Volunteer Force.
The LVF said he was not known to them.
Mr Maginness said PUP leader David Ervine could not continue to "dodge the issue or explain violence away".
PUP leader David Ervine is urged to take a "firm stand"
"The simple fact is that the UVF is engaged in murder and the planning of murder.
"Yesterday, they may have been consulting on their future, but last night they were smashing their way into a house to kill."
He called on the two governments to put pressure on loyalist paramilitaries to stop.
In response, Mr Ervine said that he did not need "lectures" from Alban Maginness.
At Mr McCausland's funeral, mourners heard Presbyterian minister Ken Doherty say that the 20-year-old had "everything to live for".
He said that his murder was "an evil deed" which left a family devastated.
Mr McCausland, a Protestant, is the second member of his family to have been murdered by loyalists.
The body of his 23-year-old mother, Lorraine, was found in a stream on 8 March 1987 near a loyalist club in Tynedale where she had been drinking.
She had been beaten with a concrete block, and it was reported at the time that it was believed she had been killed by the UDA.
Mr McCausland's murder was described as "an evil deed"
Last week, three men burst into the home Mr McCausland shared with his partner and her children and fatally wounded him.
Earlier that night, another man, David Hanley, was shot several times as he walked two dogs on the Crumlin Road near Glenbank.
A short time after the killing of Mr McCausland, in nearby Woodvale Pass, a man escaped another apparent murder bid by jumping out the window of a house as a number of masked men were attempting to smash their way in.