Sinn Fein's Martin McGuinness has resigned as deputy First Minister of Northern Ireland over Arlene Foster's refusal to stand aside during an investigation into the failed Renewable Heating Incentive.
The minister said the DUP leader could have no Executive role during the investigation.
He said Mrs Foster's refusal to show humility over the scandal was "indicative of a deep seated arrogance which is inflicting enormous damage on the Executive, the Assembly and the entire body politic".
He said it was with "deep regret and reluctance" he was tendering his resignation. He said the party would not nominate a replacement.
"We now need an election to allow the people to make their own judgement on these issues democratically at the ballot box," he said.
In an interview with the BBC the Sinn Fein MLA refused to say if he would run in a forthcoming election. The minister has suffered ill health of late.
"Today is about my resignation," he told the broadcaster, "Whether or not I will be a candidate will be something I will speak to you about at a later date."
Sinn Fein's Martin McGuinness talks about his sudden resignation, a possible election and whether he'll be well enough run in the election. pic.twitter.com/PAMiaVed2S— Mark Simpson (@BBCMarkSimpson) January 9, 2017
In a statement the MLA said his resignation was also in protest at what he called the “DUP's failure to accept the principles of power-sharing and parity of esteem”.
"Today is the right time to call a halt to the DUP’s arrogance,” he said.
"There will be no return to the status quo.”
He 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 Fein will not tolerate the arrogance of Arlene Foster and the DUP.
"Sinn Fein wants equality and respect for all.... That is what this process must be about.
The resignation comes into effect from 5pm on Monday, effectively triggering an election.
“The First Minister has refused to stand aside, without prejudice, pending a preliminary report from an investigation. That position is not credible or tenable," he said in his resignation letter.
“It is with deep regret and reluctance that I am tendering my resignation as deputy first minister with effect from 5pm on Monday, 9th January 2017."
The Sinn Fein MLA said Arlene Foster had a clear conflict of interest in the handling of the RHI scheme.
"The DUP's handling of this issues has been completely out of step with the public mood which is rightly outraged at the squandering of public money and the allegations of misconduct and corruption.
"The public are demanding robust action and accountability but the DUP, in particular Arlene Foster, have refused to accept this.
"The minister responsible for the RHI scheme should have not Executive role in overseeing how this will be rectified."
He continued: "I have urged Arlene Foster to stand aside without prejudice to ensure confidence in the necessary investigation and in the wider public interest.
"These institutions only have value if they enjoy the confidence and support of the people they were established to serve.
"They only have meaning if they are delivering fairly for all our people based on the principles of equality and mutual respect on which they were founded.
Ten years of valient service in Office Of First&DeputyFirst Minister Martin McGuinness signs resignation letter. GRMA chara 4 all Ur work. pic.twitter.com/1i4ezDTF5h— Gerry Adams (@GerryAdamsSF) January 9, 2017
Arelene your chicken is cooked! It is now over to the people to have their say on financial & political corruption. pic.twitter.com/ybIMqUTER4— John O' Dowd (@JohnODowdSF) January 9, 2017
"I have sought to maximise the potential of the institutions for forward progress in a society emerging from bitter conflict.
"But the refusal of Arlene Foster to recognise the public anger or to exhibit any humility in the context of the RHI scandal is indicative of a deep seated arrogance which is inflicting enormous damage on the Executive, the Assembly and the entire public body.
"The First Minister has refused to stand aside, without prejudice, pending a preliminary report from an investigation.
"That position is not credible or tenable."
Sinn Fein's Martin McGuinness talks about his sudden resignation, a possible election and whether he'll be well enough run in the election. pic.twitter.com/PAMiaVed2S— Mark Simpson (@BBCMarkSimpson) 9 January 2017
He added: "Over ten difficult and testing years, in the role of deputy first Minister, I have sought with all my energy and determination to serve all the people of the north and the island of Ireland by making the power-sharing government work.
“Throughout that time, I have worked with successive DUP First Ministers and, while our parties are diametrically opposed ideologically and politically, I have always sought to exercise my responsibilities in good faith and to seek resolutions rather than recrimination. I have worked tirelessly to defend our peace process to advance the reconciliation of our community and to build a better future for our young people.
Back in the early 70s in NI I found @M_McGuinness_SF terrifying. Now I have real respect for him. It took serious courage to change.— John Simpson (@JohnSimpsonNews) 9 January 2017
“At times I have stretched and challenged republicans and nationalists in my determination to reach out to our unionist neighbours. It is a source of deep personal frustration that those efforts have not always been reciprocated by unionist leaders. At times they have been met with outright rejection.
“The equality, mutual respect and all-Ireland approaches enshrined in the Good Friday Agreement have never been fully embraced by the DUP. Apart from negative attitude to nationalism and to the Irish identity and culture, there has been a shameful disrespect towards many other sections of our community.
"Women, the LGBT community and ethnic minorities have all felt this prejudice. And for those who wish to live their lives through the medium of Irish. Elements in the DUP have exhibited the most crude and crass bigotry."