A morning meeting between the Ulster Unionist leader, David Trimble, and the Sinn Fein president, Gerry Adams, the third between the two men, brought no solution.
Republicans say Mr Trimble is holding up progress by delaying the formation of the new shadow executive to run the new Northern Ireland administration, and the Good Friday Agreement entitles them to automatic places on the executive.
The Unionists say there must be IRA arms decommissioning before Sinn Fein can take executive seats: some backbenchers would revolt otherwise; republicans say IRA decommissioning is not in Sinn Fein's gift.
Mr Trimble said: "A person can't credibly say they are committed to exclusively peaceful means when they are maintaining a private army and a hoard of illegal weapons, and refusing to address the issue."
Mr Adams said: "This is not a decommissioning process. This is a peace process and a conflict resolution process."
After meeting the Taoiseach, Bertie Ahern, in Dublin an optimistic Seamus Mallon of the SDLP, said: "The problem will be dealt with... It may not be resolved to the liking of Mr Trimble, or to the liking of Mr Adams, but resolved it will be."
The head of South Africa's Truth and Reconciliation Commission, Archbishop Desmond Tutu who, on a visit to Belfast, met both Mr Trimble and Mr Adams, said: "The prize is so precious, so tremendous, that you can't allow it to be jeopardised by these manoeuvrings.
"Both of you are big enough to find a way forward."Reuse content