First Minister Peter Robinson and Deputy First Minister Martin McGuinness yesterday pledged to continue talks to end their dispute over the transfer of policing and justice powers from Westminster, despite apparent irreconcilable differences between Sinn Fein and the DUP.

The deadlock has prevented Executive meetings since June and while the two political leaders struck a conciliatory tone last night, their comments followed earlier angry exchanges between their parties.

Mr McGuinness and Mr Robinson used emergency powers last week to attend a meeting of the British-Irish Council in Scotland, but after Sinn Fein signalled they would block an Executive meeting planned for today, the DUP said a North-South Ministerial Council meeting scheduled for tomorrow may not go ahead.

Both parties have had discussions with the Secretary of State Shaun Woodward and Irish premier Brian Cowen as fears rise that the Executive is sliding towards crisis.

The two parties attacked each other publicly and privately yesterday, but when Mr Robinson and Mr McGuinness faced questions at a routine meeting of a Stormont committee in the afternoon, they sought to strike a more moderate tone.

"Well there's no disguising the reality that there are difficulties at the moment," Mr McGuinness said. "But I come from that school of thought that these are all difficulties to be overcome. I am a problem-solver, a solution-seeker, and I believe that a way through has to be found."

As the two sat in front of the committee, Mr Robinson said: "I think both the Deputy First Minister and I would be agreed on one matter entirely – when we started this process we all knew we would face times such as we are at the present time, but I don't think there is anything in either of us that is about to give up or give in on these issues."

Earlier the DUP reacted angrily when Mr McGuinness announced that talks between the parties had failed to rescue today's Executive meeting. And yesterday Mr Robinson hit back, accusing Sinn Fein of breaching their ministerial duties.

"Lest there be any doubt, let me call their bluff," Mr Robinson said.

"The only reasons that they have publicly given for the Executive not meeting are that the agenda is in some way being constrained.

"I am removing that fig leaf. I am saying we can have an open agenda, we can deal with whatever issues, including policing and justice which can be raised at the Executive table if they wish."

Mr Robinson rejected the claim that his party was opposed to real power-sharing.

"The people who are not carrying the weight of partnership are those who are not operating the institutions and that's Sinn Fein," he said.

"And there is no higher level of partnership government than the Executive itself. I want the Executive to meet.