DUP leader Ian Paisley has refused Sinn Fein's nomination to be Northern Ireland's first minister as efforts to restore devolution continue.
Ian Paisley rejected Sinn Fein's nomination to be first minister
Mr Paisley had already indicated that he intended to reject the nomination.
Sinn Fein President Gerry Adams also put forward party colleague Martin McGuinness as deputy first minister.
Declining the nomination, Mr Paisley said his "reasons were well known and had been endorsed by the majority of the unionist voters".
Despite Mr Paisley declining the first minister's post, it is still possible for members to debate policy matters under the assembly's temporary rules, although laws cannot be made.
Speaking afterwards, Mr Paisley said: "Our stand is clear, it is not going to be altered and it is simple: let's have British democracy in British Ulster."
Mr Paisley also said he would refuse to sit with Ulster Unionist leader Sir Reg Empey because of his association with PUP leader David Ervine, whose party has links to the loyalist paramilitary UVF.
The UUP's move could mean they receive an extra ministerial post, at the expense of Sinn Fein, if a government is formed.
"If Mr Empey wants the support of a terrorist organisation, let him have it, but he'll not have my support," Mr Paisley added.
Mr Adams said his party wanted to see a power-sharing executive set up as quickly as possible.
"There is a sense of wanting to get business done as quickly as possible, that is what we are about," he said.
"What we are looking for is a committee or a series of committees which will deal with the whole issue of forming the executive led by senior leaders of all of the parties.
"If that can't happen, then the DUP can only say no so many times."
The DUP have also criticised UUP leader Sir Reg Empey
The UUP's Sir Reg Empey said he hoped the assembly would be able to debate a motion calling for the establishment of a committee for the restoration of devolution.
"What we are asking the secretary of state to do is to allow a motion on the order paper for our next business to appoint a committee on the restoration of devolution," he said.
"The general public would at least know that we were actually engaged in serious business."
SDLP leader Mark Durkan said Northern Ireland's parties should face up to their responsibilities and allow other parties to do the same.
"What we have to do is to bring purpose to this whole enterprise... We have to get back to what we have been mandated to do which is to implement the Good Friday Agreement," he said.
"We will test the positions of other parties and we will test the worth of the government's word as well."
Earlier on Monday, Scottish First Minister Jack McConnell addressed assembly members at Stormont.
Northern Ireland Secretary Peter Hain invited Mr McConnell to Belfast to "highlight the benefits of devolution".
Mr McConnell said that he was not in Northern Ireland to lecture assembly members, but to offer evidence on the advantages of devolution.
"We have made great progress under devolution in Scotland. Scotland is a far better country today than it was seven years ago."
On 15 May, Northern Ireland's politicians took their seats in the Stormont assembly for the first time since October 2002.
While there is no immediate prospect of a power-sharing executive being formed, the government hopes recalling the politicians will help to pave the way towards a deal in the autumn, by its deadline of 24 November.
Devolved government was suspended over allegations of a republican spy ring. The court case that followed collapsed.
Direct rule from London was restored in October 2002 and has been in place since.