The British government will grant Northern Ireland's politicians a few days for more talks after they missed a deadline to restore a power-sharing government, Prime Minister Theresa May's spokesman said.
Northern Ireland politics has been in crisis since the collapse in January of the coalition between pro-British unionists and Irish nationalists mandated under a 1998 peace deal that ended three decades of sectarian violence.
Britain's Northern Ireland minister will make a statement on the matter on Monday, Ms May's spokesman said. James Brokenshire earlier called for a solution "as soon as possible", without outlining a new timetable.
"A number of outstanding issues remain. I believe that a resolution can be found and I am urging the parties to continue focusing all their efforts on achieving this," Mr Brokenshire told reporters.
The Irish and British governments - who are facilitating the talks - have warned that a failure to reach an agreement would have "profound and serious" implications and limit Northern Ireland's influence in negotiations on Britain's exit from the European Union.
The British-run province risks fresh elections or reverting to direct rule from London for the first time in a decade if power-sharing cannot ultimately be restored.
The talks are mainly stuck on a disagreement between the pro-British Democratic Unionists Party (DUP) and its closest rival, Irish nationalists Sinn Fein, over Sinn Fein's demand to give the Irish language legal status in the province.
"We have been met with an anti-equality and anti-rights agenda," Sinn Fein regional assembly member Conor Murphy told reporters. "We are trying to get past that, but we're not there yet."
The two rival parties shared power for a decade until Sinn Fein pulled out of government in January.