The leader of North Ireland's Democratic Unionist Party (DUP), Jeffrey Donaldson, warned against a referendum on Irish unity, which he called "divisive".

Pro-Irish nationalists Sinn Fein are expected to become the largest party in Northern Ireland's regional assembly, with voters heading to the ballot box on Thursday.

Sinn Fein's win could enable the former political wing of the paramilitary IRA (Irish Republican Army) to lead a power-sharing government for the first time.

Pro-UK unionists, like the DUP, have held power for over a century since Northern Ireland was created. The unionists are arguing that Sinn Fein will use power to push for a referendum on re-joining the Republic of Ireland, its neighbor to the south.

"Sinn Fein want to work in alliance with dissident republicans, people who are continuing to engage in violence, people who have committed murders on our streets in Northern Ireland," DUP leader Jeffrey Donaldson said. 

The New IRA, one of many dissident republican paramilitary groups opposed to the shift toward non-violence advocated by Sinn Fein, has admitted responsibility for the 2019 slaying of journalist Lyra McKee.

Election posters are strewn throughout the province's main thoroughfares and intersections. A Sinn Fein billboard near the Irish border in Newry proclaims "Irish reunification" as "the solution to Brexit."

Sinn Fein leader Michelle O'Neill said that there has been a seismic shift in society, particularly in the aftermath of Brexit, which "we didn't vote for, but which has been foisted upon us."

However, the party is downplaying the possibility of a united Ireland in the near future, fearful of alienating centrist supporters and moderate unionists who are concerned about healthcare, education, and the UK's cost-of-living crisis.