Martin McGuinness has told unionist leaders to confront loyalists and stop allowing "extreme elements within their community" to set their agenda on the Haass proposals.
The deputy First Minister issued his blunt warning after a meeting of the five Executive party leaders to discuss former US diplomat Dr Richard Haass' plan to deal with Northern Ireland's most divisive issues – flags, parades and the legacy of the Troubles.
The most senior Sinn Fein MLA said: "We made it clear our opposition to renegotiation or time wasting through the establishment of some sort of working group.
"What is required and what people want to see is implementation."
He called on unionist leaders "to confront the extreme elements within their community who they are letting set their agenda on Haass to date and former members of the RUC and other Crown forces lobbying the DUP and the UUP to prevent truth recovery processes which are victim centred."
He added: "If they do this then it is my belief that we can reach agreement and press ahead with implementation."
The first meeting of the party leaders came the day after an Assembly debate on the Haass proposals. There were attempts by the UUP, DUP and Alliance to amend the Sinn Fein motion urging implementation.
But neither the proposal nor any amendments were passed.
Dr Alasdair McDonnell, the SDLP leader, yesterday predicted that the Assembly might soon move to implementing and legislating for some aspects of the Haass proposals.
He delivered a cautiously upbeat assessment after the 90-minute leaders' meeting, which is due to reconvene next Tuesday.
"It is my view that we have had enough process and that the issues are now over to the five party leaders to be sorted out and I am keen to get some sort of an implementation process for the things that we agree on. We (need to) get legislation on those things and get resolution on the issues," Dr McDonnell said.
Asked if there had been general agreement around the table, he said: "We had a lot of discussion and some differences but agreement to meet again very soon.
"There are some outstanding issues to be resolved and we fully respect each other's positions. We will be coming forward in due course with a timetable."
No comment was forthcoming from the DUP.
Mike Nesbitt of the UUP confined himself to confirming "we will meet again very soon".
On Monday, First Minister Peter Robinson, the DUP leader, said the meeting would be about selecting which of 340 points in the Haass document were accepted by everybody and then trying to narrow down the gap on the rest. Nationalists were suspicious that this could mean a time- consuming renegotiation.
Both nationalist parties are keen to start implementing the Haass proposals and are strongly opposed to extensively renegotiating them.
Some participants in yesterday's meeting pointed to an earlier statement by Mr Robinson, that the "broad architecture" of the Haass proposals were acceptable even if the detail was not.
Mr McGuinness echoed this language, saying: "I am ready and willing to move forward with all of the other party leaders. The Haass architecture allows this to happen."