Efforts to form a powersharing government in Stormont were deadlocked on Monday night after DUP leader Jeffrey Donaldson said his party would not go back into the Executive until there was "decisive action" on the Northern Ireland protocol.
Speaking following a meeting with Northern Secretary Brandon Lewis in Belfast, Mr Donaldson said his party had made its position "clear".
He said it was “the position we have held before the election, throughout the election campaign and will continue to hold, and that is until we get decisive action taken by the UK government on the protocol we will not be nominating ministers to the Executive.”
The Assembly is due to meet for the first time on Friday but, without a DUP nomination for deputy first minister, a new Executive cannot be formed.
With no immediate prospect of a resolution, the North is facing a long period of political stalemate which could last up to six months and, potentially, a fresh election.
The other Northern parties and the Irish, British and US governments have urged the DUP to nominate a deputy first minister who would share office with Sinn Féin’s Michelle O’Neill as first minister.
In a press conference at Parliament Buildings on Monday, Sinn Féin leader Mary Lou McDonald said the “job now is to get to work” and called for the “immediate formation of an Executive, Michelle O’Neill ratified as first minister and an appointment of a deputy first minister.”
She warned "any tactics of delay from the DUP, any grandstanding by them, any gamesmanship from the British government who may wish to use the north of Ireland as a bargaining chip in terms of their wider engagement with the European Union over the protocol, would be clearly intolerable."
Talks on possible changes to how the protocol works are expected to resume shortly and senior sources in Dublin said they expected a difficult few months of negotiations between the EU and UK, with a lack of trust between the two sides likely to make achieving progress harder.
EU and Irish ministers will closely watch the Queen’s speech - to be delivered in her abence on Tuesday by Prince Charles - for indications the British government is considering unilaterally setting aside parts of the protocol – which the EU has made clear would attract a significant response, including, potentially, giving notice that the entire withdrawal treaty could be voided.