Sinn Fein and the nationalist SDLP have hailed the Stormont election results which have seen both parties fare strongly and Northern Ireland's Unionist parties lose overall control of the region's Assembly for the first time in over a century.

The Democratic Unionist Party (DUP) remains the largest party with 28 of the 90 available seats, just one more than Sinn Fein which now have 27.

Overall turnout was high at 64.8% of the electorate. The DUP failure to win 30 seats means they will be unable to block same-sex marriage in the province.

The gains by Sinn Fein and SDLP mean the Assembly is now equally split between nationalist and unionist factions.

The SDLP becomes the third biggest party, but the Ulster Unionists (UUP) slipped to fourth, prompting the resignation of leader Mike Nesbitt.

He told journalists at the Park Avenue Hotel in Belfast: "Some day Northern Ireland will vote as a normal democracy. We will vote in a post-sectarian election, but it's now clear it will not happen during the duration of my political career."

In contrast, Michelle O'Neill, of Sinn Fein, which attracted a 27.9% share of the votes, said the results were "a brilliant day for equality… a great day for democracy."

Ms O'Neill took over the helm of the nationalist party from Martin McGuinness, who stepped aside due to illness in January 2017 after the collapse of the Northern Ireland Assembly because of a scandal over green energy policies.

Under Northern Ireland's power-sharing agreement, Sinn Fein and the DUP must now form a coalition within three weeks or face the prospect of power being returned to Westminster. But this may prove problematic: Sinn Fein has demanded the resignation of former first minister Arlene Foster, who won her seat and made a plea for civility to return to politics.

"Let us now move forward with hope, hope that civility can return to our politics," Ms Foster told supporters, speaking to Sky News. "There is work to be done to quickly mend the relationship which has been frayed by the discord of this election."

How Northern Ireland voted

PartySeatsVotesChange
Democratic Unionist Party (DUP)2828.1%-1.1%
Sinn Féin2727.9%+3.9
SDLP1211.9%-0.1%
Ulster Unionist Party (UUP)1012.9%+0.3%
Alliance Party89.1%+2.1%
Green Party22.3%-0.4%
Others36.2%