Brexit supporters carry flags and placards as they walk down Whitehall in central London on Jan 31, 2020 on the day that the UK formally leaves the European Union.(Glyn KIRK / AFP)

The UK hit back at remarks by European Union officials over Northern Ireland, warning the bloc to take the British government’s threat to suspend parts of the post-Brexit settlement “seriously.”

Britain and the EU are locked in a dispute over the future of Northern Ireland, which effectively remained in the bloc’s single market and customs union following Brexit to avoid creating a trade border within the island of Ireland.

ALSO READ: EU rejects UK demand to renegotiate N. Ireland protocol

Instead, the border was placed in the Irish Sea, disrupting the flow of goods between Northern Ireland and the rest of the UK. The British government wants to rewrite the settlement and has said current trade conditions justify it unilaterally suspending parts of the so-called protocol.

“There must be a real negotiation between us and the EU,” UK Brexit minister David Frost told the House of Lords on Monday. “A real negotiation does not mean the EU coming up with its own plans for solutions, within the framework of the existing protocol, and presenting them to us as ‘take it or leave it’.”

Speaking in Northern Ireland last week, European Commission Vice President Maros Sefcovic said he is committed to easing the flow of goods and fixing issues raised by Brexit, but that the EU won’t pursue a full renegotiation

ALSO READ: UK warns of 'cold mistrust' if EU does not move on N. Ireland

Speaking in Northern Ireland last week, European Commission Vice President Maros Sefcovic said he is committed to easing the flow of goods and fixing issues raised by Brexit, but that the EU won’t pursue a full renegotiation.

“A renegotiation of the protocol -- as the UK government is suggesting -- would mean instability, uncertainty and unpredictability in Northern Ireland,” he said. “Bear in mind it has already taken us five years to get to this point.”

Article 16 of the Northern Ireland protocol allows one side to suspend parts of the agreement if it is causing disruption to trade. The other side can in turn take retaliatory action.

READ MORE: UK warns of 'cold mistrust' if EU does not move on N. Ireland