Belfast: The Irish National Party Sinn Fein has won the assembly elections in Northern Ireland. When all the votes were counted, Sinn Fin won 27 of the 90 seats in the legislature.

The Democratic Unionist Party, which has dominated Northern Ireland's legislature for two decades, captured 24 seats.

The victory means Sinn Fein is entitled to the post of first minister in Belfast for the first time since Northern Ireland was founded as a Protestant-majority state in 1921.

The centrist Alliance Party, which doesn't identify as either nationalist or unionist, saw huge surge in support and was set to become the other big winner in the vote, claiming 17 seats.

The victory is a milestone for Sinn Fein, which has long been linked to the Irish Republican Army, a paramilitary group that used bombs and bullets to try to take Northern Ireland out of U.K. rule during decades of violence involving Irish republican militants, Protestant Loyalist paramilitaries and the U.K. army and police.

O'Neill stressed that it was imperative for Northern Ireland's politicians to come together next week to form an Executive, the devolved government of Northern Ireland.

If none can be formed within six months, the administration will collapse, triggering a new election and more uncertainty.

There is "space in this state for everyone, all of us together," O'Neill said. "There is an urgency to restore an Executive and start putting money back in people's pockets, to start to fix the health service. The people can't wait."

While a Sinn Fein win would signal a historic shift that shows diminishing support for unionist parties, it's far from clear what happens next because of Northern Ireland's complicated power-sharing politics and ongoing tussles over post-Brexit arrangements.

Under a mandatory power-sharing system created by the 1998 peace agreement that ended decades of Catholic-Protestant conflict, the jobs of first minister and deputy first minister are split between the biggest unionist party and the largest nationalist one.

Both posts must be filled for a government to function, but the Democratic Unionist Party has suggested it might not serve under a Sinn Fein first minister.