Northern Ireland First Minister Paul Givan is preparing to announce his resignation, a senior Democratic Unionist Party (DUP) source says.
It is thought an announcement will come by the end of the week – potentially later today.
Senior DUP figures are set to meet later on Thursday to confirm the timing of Mr Givan’s resignation statement, the PA news agency understands.
The reports come less than 24 hours after DUP Agriculture Minister Edwin Poots ordered a halt to agri-food checks at Northern Ireland ports.
It is believed the move is part of the DUP’s protest against the Northern Ireland Protocol – part of the Brexit deal which was agreed by both sides and is designed to prevent a hard border on the island of Ireland.
Mr Givan’s resignation would automatically remove Sinn Fein deputy first minister Michelle O’Neill from office as Northern Ireland’s power-sharing arrangements mean the roles of first and deputy first ministers are a joint office shared between the two largest parties at Stormont.
The DUP, as the the biggest party in Stormont, hold the first minister’s post.
If Mr Givan were to resign, it is believed other ministers in the administration could stay in place to oversee their departments, but that the executive would be unable to make any significant decisions – such as agreeing the three-year-budget spending plan which is currently under public consultation.
Mr Poots issued a direction on Wednesday evening, instructing officials to stop the agri-food checks at midnight.
However, there has been no confirmation from Stormont officials whether they intend to comply with the order.
The status of Brexit checks at ports remains unclear as of Thursday morning as lorries were still being received at a Department of Agriculture, Environment and Rural Affairs (Daera) checking facility in Belfast Port.
A staff member declined to confirm to the PA news agency whether the agri-food checks required under the Northern Ireland protocol were continuing.
The European Commission has said the decision creates “further uncertainty and unpredictability”.
“The European Commission has been working tirelessly with the UK government to address practical challenges related to the implementation of the protocol,” a spokesperson for the Commission said.
“The decision by the Northern Irish minister for agriculture (Edwin Poots) is therefore unhelpful. It creates further uncertainty and unpredictability for businesses and citizens in Northern Ireland.
“The European Commission will closely monitor developments in Northern Ireland pursuant to this announcement.”
The spokesperson added that Vice President of the European Commission, Maros Sefcovic, will speak to Foreign Secretary Liz Truss on Thursday afternoon to continue negotiations aimed at reducing the number of checks required by the Northern Ireland protocol.
The UK government has said it will not intervene in what it has characterised as a matter that falls to Stormont.
Mr Givan was appointed first minister just over eight months ago in June 2021.