DUP leader Arlene Foster has said that Northern Ireland would leave the EU on the same terms as the rest of the United Kingdom, rebuffing a suggestion from the bloc that the region remain subject to some of its rules.
Brussels has said it will not move to the second phase of Brexit talks with Britain until London provides additional detail of how it will guarantee that there be no hard border between Northern Ireland and the Republic.
Today, Chief EU Brexit negotiator Michel Barnier asked the British government to detail what specific EU rules it would retain in Northern Ireland to ensure regulatory equivalence between the region and the Republic and thus avoid the need for a hard border.
But Ms Foster repeated her rejection of the suggestion, saying she would not create barriers to business with the rest of the United Kingdom to allow smooth trade with Ireland.
"Northern Ireland will exit the EU on the same terms as the rest of the United Kingdom," she said in a statement ahead of a meeting with British Prime Minister Theresa May tomorrow morning.
"We will not countenance a border in the Irish Sea. I welcome the Prime Ministers commitment on this," she said.
The EU has said that Britain needs to come forward with concrete proposals on the Irish border and on what past financial commitments it will honour by early December if EU leaders are to declare at their next summit that enough has been achieved to start talks on a transition period and a trade deal.
The next European summit is due to take place on 14-15 December.
Britain is scheduled to leave the bloc in March 2019.
Ms Foster said the EU's stance on Northern Ireland amounted to blackmail.
She said: "Those in Dublin and Brussels, recklessly trying to use Northern Ireland for their own objectives, should cease.
"The Prime Minister should warn Brussels that Northern Ireland must not be used as blackmail."