LONDON — The leader of the senior party in Northern Ireland’s government resigned late Thursday after colleagues revolted over a deal to appoint new leaders to the Protestant-Catholic power-sharing administration.

Edwin Poots, who was elected just a month ago, announced he was quitting as leader of the Democratic Unionist Party following a meeting of senior party officials. Poots said he would stay in the post until a new leader was elected.

“This has been a difficult period for the party and the country and I have conveyed to the chairman my determination to do everything I can to ensure both Unionism and Northern Ireland is able to move forward to a stronger place,” he said.

The statement came hours after Poots nominated DUP legislator Paul Givan to be Northern Ireland’s new first minister. Michelle O’Neill of Irish nationalist party Sinn Fein was reappointed deputy first minister.

The appointments appeared to resolve a crisis that had threatened to sink Northern Ireland’s power-sharing administration.

Sinn Fein had threatened not to fill the post of deputy because of a feud about protections for the Irish language. That would have mothballed the administration — under the power-sharing arrangements set up as part of Northern Ireland’s peace accord, a government can’t be formed unless both roles are filled.

The language issue cuts to the heart of tensions between Northern Ireland’s mostly Catholic nationalists, who see themselves as Irish, and Protestants, who largely identify as British.

The Northern Ireland Assembly, in which the DUP is the largest party, has failed to pass a law ensuring protections for the Irish and Ulster Scots languages, despite the power-sharing parties agreeing last year to do so.

But after crisis talks with the two parties, the British government said early Thursday it would step in and pass the legislation in the UK Parliament if the Belfast assembly did not do it by September.

Sinn Fein welcomed the move, with party leader Mary Lou McDonald saying it had broken the “logjam of DUP obstructionism.” Poots accused Sinn Fein of creating instability, but agreed to nominate a first minister.

That provoked fury from many DUP colleagues.

“You cannot lead people who are not following you,” DUP lawmaker Sammy Wilson said as he entered Thursday’s party meeting. “If you have no followers, you can’t be a leader, can you?”

The latest crisis was triggered by the resignation of Arlene Foster as first minister and DUP leader. She quit in April, under pressure from her party over her handling of Brexit and her perceived softening on social issues such as abortion and LGBT rights.

By the narrowest of margins the party elected Poots, a social and religious conservative, to replace Foster as leader. He broke with tradition by deciding not to serve as first minister.

Poots was elected May on 14, formally ratified as leader on May 27 and resigned 21 days later, making him the shortest-serving leader in the party’s history.

he DUP, which is rooted in the fundamentalist Free Presbyterian Church, opposed Northern Ireland’s 1998 peace accord. It later became reconciled to it and has shared power with the Irish Republican Army-linked Sinn Fein.

The British government retains an array of powers affecting Northern Ireland, but the Belfast assembly can make laws in areas including agriculture, education and health.

The power-sharing relationship has often been strained, and Britain’s economic split from the European Union at the end of 2020 has further shaken the political balance in Northern Ireland.

Post-Brexit trade rules have imposed customs and border checks on some goods moving between Northern Ireland and the rest of the UK, angering Northern Ireland’s British unionists who say the new checks amount to a border in the Irish Sea and weaken ties with the rest of the UK.

Tensions over the new rules contributed to a week of street violence in Northern Irish cities in April that saw youths pelt police with bricks, fireworks and gasoline bombs.