Britain's Northern Ireland minister will urge leaders of the province's political parties on Monday to form a new post-election power-sharing government, a challenge made more difficult by unresolved Brexit issues.
Irish nationalist party Sinn Fein won the most seats in the Northern Ireland's devolved assembly for the first time last week, a result it said was a "defining moment" for the British-controlled region.
It has the right to put forward a candidate for first minister in Northern Ireland's power-sharing government, set up under a 1998 peace deal that ended three decades of sectarian conflict in the province.
But the pro-British Democratic Unionist Party (DUP) has said it will not participate until there is a breakthrough in post-Brexit rules that impose trade barriers between the province and the rest of the United Kingdom.
Britain's Secretary of State for Northern Ireland, Brandon Lewis, will meet Sinn Fein leader Michelle O'Neill, her DUP counterpart Jeffrey Donaldson, and the leaders of the Alliance, UUP and SDLP parties, the British government said.
"The people of Northern Ireland deserve a stable and accountable devolved government," he said in a statement.
British Deputy Prime Minister Dominic Raab said on Sunday Northern Ireland's political stability was in peril until problems with the protocol governing post-Brexit trade were fixed.
Lewis said London "would not shy away from taking further steps if necessary" to address the protocol if agreement with the European Union could not be reached.
"However, the people of Northern Ireland need a stable and accountable government that delivers on the issues that are important to them," he said.
The EU's envoy to Britain said the bloc was ready to restart talks on the protocol after a pause for the elections but would not overhaul the arrangement that is central to post-Brexit trading rules.
"Let's be clear: we are not ready to renegotiate an international treaty that we signed just a couple of years ago," Joao Vale de Almeida told BBC radio on Monday.
"But also it is clear in our mind that unilateral action creates more problems than the ones it solves. So we need to find jointly agreed solutions."
Vale de Almeida said the EU was ready to talk with the Unionist politicians about their fears over the protocol.
Irish Prime Minister Micheal Martin said any further setbacks in the talks would prove that Brexit was not yet settled, but there was a "landing zone" to smooth trade. "The European Union will need an indication that people are in the mood for settling this and resolving this, that it can't be one more concession after another," Martin said.
