BELFAST (Reuters) – The head of the Democratic Unionist Party said on Monday 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 Ireland and Northern Ireland.

Chief EU Brexit negotiator Michel Barnier on Monday 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 Irish Republic and thus avoid the need for a hard border.

But the head of the DUP, whose votes the government of British Prime Minister Theresa May is dependent on to pass legislation, repeated her rejection of the suggestion on Monday, 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,” Arlene Foster said in a statement ahead of a meeting with May on Tuesday morning.

“We will not countenance a border in the Irish Sea. I welcome the Prime Minister’s commitment on this.”

The EU has said the UK 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 Dec. 14-15 summit that enough has been achieved to start talks on a transition period and a trade deal.

Britain is scheduled to leave the bloc in March 2019.

Foster said the EU’s stance on Northern Ireland amounted to blackmail.

”Those in Dublin and Brussels, recklessly trying to use Northern Ireland for their own objectives, should cease,“ she said in the statement. ”The Prime Minister should warn Brussels that Northern Ireland must not be used as blackmail.