The Ulster Unionist leader, David Trimble, says that in his talks with Sinn Féin's Gerry Adams, he has not yet received the assurances he needs that the IRA will cease all paramilitary activities.
Mr Trimble said the attempts to break the political deadlock in advance of new assembly elections will not fail for lack of effort on his part.
The two are due to hold more talks this weekend.
Early next week, the British prime minister, Tony Blair, is expected to announce if postponed Assembly elections in the North will go ahead next month.
