In this image taken from video, Deputy First Minister Martin McGuinness announces his resignation, Jan. 9, 2017, with the declared intention of triggering early elections in Northern Ireland. (ITN via ASSOCIATED PRESS)

The future of Northern Ireland’s power-sharing government has been cast in doubt after Martin McGuinness resigned Monday as the region’s deputy first minister in protest over the handling of a renewable energy project.

The move by McGuinness, a towering figure in the Sinn Fein party and the deputy first minister for nearly 10 years, could trigger fresh elections in the region.

Power sharing has been central to a fragile peace in Northern Ireland, where Irish nationalists opposed to British rule battled unionists who wanted to keep the region part of the United Kingdom. Under rules outlined in the 1998 Good Friday Agreement, which helped end decades of bloodshed, Northern Ireland’s regional legislature requires the support of both the first minister and the deputy first minister — the positions have equal power. If either one resigns and a replacement is not found, the government will fall.

McGuinness has repeatedly called on Arlene Foster, the Democratic Unionist Party (DUP) leader and first minister, to temporarily step aside while investigators review her alleged mishandling of a renewable energy plan.

“Sinn Fein will not tolerate the arrogance of Arlene Foster and the DUP. We now need an election to allow the people to make their own judgment,” McGuinness said in a statement.

Foster has steadfastly refused to withdraw. “If Sinn Fein are playing a game of chicken and expecting me to blink in terms of stepping aside, they are wrong,” she recently told the Impartial Reporter newspaper. “If there is an election, there is an election.”

The clock is ticking. Sinn Fein has seven days to nominate a replacement deputy first minister, but McGuinness has said the party has no intention of doing so. If there are new elections, it’s unclear whether McGuinness would be a candidate. McGuinness, a former Irish Republican Army commander, has been at the center of the provincial government since 2007, but commentators say the 66-year-old is suffering from unspecified health problems.

The main cause of the dispute between the parties stems from a botched program that was designed to encourage businesses to switch to renewable energy sources. The program, which Foster oversaw in a previous post, went several million pounds over budget and has been criticized for its inefficient subsidies.

Although the scandal probably would be a big issue in new elections, Britain’s exit from the European Union could also feature prominently. The Democratic Unionist Party backed the campaign to leave the E.U., while Sinn Fein campaigned for Britain to remain in the bloc.

After the Brexit vote, McGuinness called for a referendum on whether Northern Ireland should join the Republic of Ireland, which is in the E.U.

Foster said Friday that she was “disappointed” by McGuinness’s resignation. She said it was “clear that Sinn Fein's actions are not principled; they are political.”