There can be no Brexit agreement without a backstop option for the Irish border, EU chief negotiator said.
Michel Barnier said the Republic of Ireland has the full support of all EU Member States and all EU institutions.
The backstop would involve NI or the entire United Kingdom and follow the EU rules needed to support North-South cooperation and a total island economy.
Mr Barnier spoke at the beginning of a two-day visit to Ireland.
Britain has accepted that an emergency brake must be written into the Brexit exit agreement
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But it has not agreed what the EU should govern
At the start of the Brexit Islandwide Forum in Dundalk, County Louth, Barnier said he knew that the so-called "backstop" had been the subject of "heated discussions in the UK".
"To be clear, there can be no repurchase agreement without a bailout," said Barnier. "This is an EU issue, not just an Irish question"
Mr Barnier also denies allegations made by Arlene Foster, leader of the Democratic Unionist Party (DUP), that he was "aggressive" The Trade Unionists of Northern Ireland at the Brexit Talks
The DUP leader said before that Barnier did not understand the dispute and was not an "honest broker."
The Brexit chief negotiator then said he was not ready to "polemic" with Ms. Foster.
Barnier's visit comes amid increasing tensions over the future British-Irish border.
He said at a press conference in Dundalk at the start of the Island Brexit Forum, his "door is open to Ms. Foster and the DUP.
He said he did not approach the negotiations in a "spirit of revenge."