Sinn Fein repeated its calls yesterday for the release of those responsible for the death of Det Garda Jerry McCabe.
Mr Gerry Kelly MLA said the Government's position that the four IRA men involved would not be released "flies in the face of the Good Friday agreement".
Speaking on the BBC, he said: "There was a Good Friday negotiation and prisoners were part of that. These men belonged to the IRA . . . You cannot have a two-tier system."
Mr Kelly said Sinn Fein negotiators had "made it clear that qualifying prisoners meant all republican and political prisoners".