Northern Ireland’s first minister intends to resign later on Thursday in protest at post-Brexit trade rules, the BBC reported as the European Union warned Britain that it would breach international law if it lets Belfast halt some checks on goods.

Tensions over the Northern Ireland protocol, signed as part of Britain’s exit from the EU, flared again on Wednesday when the British province’s Agriculture Minister Edwin Poots ordered an immediate halt to checks on agri-food goods coming into the region from the rest of the United Kingdom.

Poots’ pro-British Democratic Unionist Party has for months also threatened to pull down the regional government ahead of an election in May over its vehement opposition to the protocol, which the DUP believes drives a wedge between the region and the rest of the UK across the Irish Sea.

The protocol kept Northern Ireland in the EU’s customs union for goods in order to preserve a politically sensitive open border with EU member state Ireland. In so doing, though, it created an effective border in the Irish Sea, angering pro-British, pro-Brexit unionists and prompting the British government to seek to rewrite the deal it signed up to in 2019.

The BBC reported that First Minister Paul Givan would make a resignation announcement later on Thursday, though he may not stand down until next week.

Asked about the report, Poots told the BBC: “I think you’ll just have to wait and see what happens during today, if that happens or not.” A spokesperson for the DUP could not immediately be reached for comment.

If Givan quits, it will trigger the resignation of Deputy First Minister Michelle O’Neill of the DUP’s Irish nationalist and pro-EU rivals Sinn Fein. This would paralyse decision-making in the region where the main parties share power under a 1998 peace deal that ended three decades of sectarian violence.

It would not necessarily lead to early elections, which opinion polls suggest will see Sinn Fein pass the DUP to become Northern Ireland’s largest party for the first time.

The DUP have lost support to other unionist groups over the protocol.

CHECKS NOT HALTED YET

Poots also told the BBC that his officials had “I’s to dot and T’s to cross” before halting the checks and that this would take a matter of days. Trade bodies reported on Thursday that goods were still being inspected at Northern Irish ports.

In London, the British government said the checks were a matter for Northern Ireland’s devolved executive. But Ireland’s foreign minister said London has an obligation to comply with international law, a view echoed by EU Financial Services Commissioner Mairead McGuinness.

“It’s an absolute breach of international law,” McGuinness, Ireland’s representative on the executive European Commission, told national broadcaster RTE.

“We have reminded our UK counterparts from the very outset when they pulled away from implementing the agreement that they were breaching international law. That is a major problem because we need to be able to trust each other.”

A spokesman for the Commission added that Poots’ decision was unhelpful, created further uncertainty for Northern Irish business and that London had a responsibility to respect the international obligations it had entered into under Brexit.

The European commissioner dealing with the protocol, Maros Sefcovic, is due to speak to British Foreign Secretary and Brexit negotiator Liz Truss later on Thursday.