Irish nationalist party Sinn Fein has accepted a deal approved by Northern Ireland's other main parties to resume power-sharing after a three-year suspension.
"The Sinn Fein Ard Chomhairle [national executive] has met today and has taken the decision to re-enter the power-sharing institutions and to nominate ministers to the power-sharing executive," Sinn Fein leader Mary Lou McDonald told reporters on Friday.
A compromise deal was drafted by the British and Irish governments late Thursday after several days of talks in Belfast involving Northern Ireland's five main political parties.
The last-minute deal should allow the British government to avoid calling elections to Northern Ireland's devolved assembly, which would have been required if no agreement were reached by Monday.
Sinn Fein, which seeks a united Ireland, and the Democratic Unionist Party (DUP), which wishes to remain in union with Britain, have shared power for most of the years following the 1998 Good Friday Agreement which underpins Northern Ireland's fragile peace process.
McDonald said the politicians faced "serious challenges," including the impact of Brexit.
"The biggest and most significant challenge will be ensuring that we have genuine power sharing based on equality, respect and integrity," she said.
"It requires everyone to step up," she said.
"At these historic times we will also continue to work for Irish reunification and we want to ensure that the criteria for the triggering of an Irish unity poll are set out and that planning for Irish unity is stepped up," McDonald added.
The DUP and the other parties had earlier signalled their acceptance of the draft agreement, despite reservations.
"On balance we believe there is a basis upon which the assembly and executive can be re-established in a fair and balanced way," DUP leader Arlene Foster said.
"This is not a perfect deal and there are elements within it which we recognise are the product of long negotiations and represent compromise outcomes," Foster said, adding that "there will always need to be give and take."
The impasse began in January 2017 with the resignation of late Sinn Fein politician Martin McGuinness as deputy first minister to Foster, and his party's refusal to nominate a successor.
