The Ulster Unionist Party leader, Mr David Trimble, said yesterday that he would not sit in cabinet with the Sinn Fein leader, Mr Gerry Adams, "for the foreseeable future", until Mr Adams "demonstrated clearly that he was committed entirely to peaceful means".
Mr Trimble said he knew individuals could change, and added: "I am not saying `absolutely never' with regard to that individual, but he has a long, long way to go."
Mr Trimble criticised unionists calling for a No vote in the referendum, accusing them of "political cowardice".
"I am sick of listening to the tired rhetoric of those who have failed the unionist people in the past," he said, when the UUP launched its campaign for a Yes vote in Belfast.
The alternatives being offered by the No campaign "were neither credible nor achievable". He accused them of "scaremongering" and said they had run away from negotiations last year and would run away again if they were faced with a similar challenge.
It was time, he said, for unionists "to get up off their knees", have confidence in themselves and embrace this opportunity.
The party deputy leader, Mr John Taylor, issued a list of what he described as "cross-Border bodies" created since the AngloIrish Agreement by the two governments. Under the Belfast Agreement, the pro-British majority would have the power of veto on North-South co-operation, he said.
The DUP later said the Ulster Unionists had not launched, but relaunched their Yes campaign. "They have launched again but they still haven't got off the ground," Mr Ian Paisley jun said.