Arlene Foster says she’s “disappointed” that Martin McGuinness has stood down as Deputy First Minister.
The resignation of Mr McGuinness is likely to result in an election within weeks as Sinn Féin firmly insist that they won’t be nominating a replacement.
Under power sharing this means that Arlene Foster has lost her post as First Minister.
The resignation comes as a result of the RHI scandal which was approved by Arlene Foster and could end up costing taxpayers half a billion pounds. But Mr McGuinness also identified a number of other issues which he said had forced him to take action.
Tendering his resignation yesterday Martin McGuinness said: “Over the last ten years I have worked with DUP leaders and reached out to unionists on the basis of equality, respect and reconciliation.
"Over this period the actions of the British government and the DUP have undermined the institutions and eroded public confidence
"Sinn Féin will not tolerate the arrogance of Arlene Foster and the DUP. Sinn Féin wants equality and respect for all. That is what this process must be about. Today I tendered my resignation.
"Today is the right time to call a halt to the DUP’s arrogance.There will be no return to the status quo.”
Secretary of State James Brokenshire hopes a deal can be worked out in the week that remains before the Assembly officially stands down. He said: “I would urge the political parties to work together to find a solution to the current position and we will be doing all that we can with the political parties and the Irish government to that end.”
Mr Brokenshire is expected to make a statement at Westminster at midday today.
Sinn Féin President Gerry Adams TD has said Mr McGuinness has taken decisive action in resigning as Deputy First Minister.
He said: "Martin McGuinness has led from the front in the Executive for the last ten years, defending the integrity of the political institutions and realising the potential of the Good Friday Agreement.
"He has worked with successive DUP leaders and is recognised throughout the north, across Ireland and across the world for his leadership and peacemaking.
"In spite of the provocation, disrespect and arrogance from the DUP, and the failures of the British government to fulfil its responsibilities over that time, Martin McGuinness has always put the people and the political process first.”
He added: "This is in contrast to the DUP who have been acting to undermine equality and partnership.
"The money squandered in the RHI project belonged to unionists as well as other taxpayers. It is money which should have been used to end poverty and disadvantage or to build public services. No minister responsible for such bad governance in any other administration would be still in office.”
Alliance Leader Naomi Long pointedly Tweeted shortly after the announcement: “So @M_McGuinness_SF resigns as DFM. Clock now is ticking for election. Wonder what @DUPleader sees through her love glasses today? #RHI.”
People Before Profit MLA Gerry Carroll posted on Facebook: “RHI is not the first scandal. And no doubt it won’t be the last. We need a new politics, that puts the interests of people before the interests of private profit, and that seeks to unite working class people across the divide.
“It looks like an election will called. It should be called. Let the people have their say.”