Sinn Fein leader Gerry Adams has called on loyalists to withdraw threats against republicans.
Following his party's first meeting with the leadership of the Northern Ireland Policing Board, the West Belfast MP said the threats were unacceptable.
"I want to deal briefly with the issue of a number of citizens having been warned that they are actively under threat from, I believe, the Ulster Volunteer Force - although I cannot say that authoritatively," he said.
"That is what I believe to be the organisation behind that threat.
"It is totally unacceptable and we look to the threat being withdrawn and to be withdrawn in a very, very public manner as quickly as possible."
Republicans in Londonderry and North Antrim have in recent days been warned of a security risk of attack from loyalists.
The Sinn Fein leader described the meeting with Policing Board chairman Sir Desmond Rea and vice chairman Barry Gilligan as another important step in his party's quest for accountable and effective policing on both sides of the Irish border.
The West Belfast MP would not be drawn on who his party's three nominees for the Policing Board would be.
But he confirmed: "I have to go to an ard chomhairle meeting post May 8 and it is my firm intention when we have an ard chomhairle meeting on May 12 to make a proposal that we take up our positions on the Policing Board.
"I have given notice to the ard chomhairle of that intention and that's all in the expectation and very firm conviction that on May 8 we will see the institutions here reconstituted and the Executive in place."
