Europe needs to hear and understand unionist concerns about the backstop to avoid a hard border in Ireland, DUP leader Arlene Foster has said.
At a meeting in Brussels, she told European Union chief Brexit negotiator Michel Barnier that unionists opposed the Withdrawal Agreement because of the contentious mechanism.
Afterwards, she warned that the UK and EU would move "inexorably towards a no-deal scenario" if changes to the backstop were not made.
Mrs Foster's meeting comes after British Prime Minister Theresa May accepted an offer from leaders of the 27 EU countries to delay the deadline for Brexit to 31 October.
Mrs Foster contends that the EU has ignored the feelings of unionists on the issue, and has instead been influenced by the pro-backstop lobbying of Irish nationalists.
Conservative MPs and fellow Brexiteers Iain Duncan Smith and Owen Paterson accompanied Mrs Foster to the meeting with Mr Barnier today.
They are also seeking a Brexit deal that does not contain a backstop.
Afterwards, the DUP leader said: "We wanted to have the unionist voice heard so that he could hear the impact of the backstop and what it will do to the balance in Northern Ireland.
"We had good engagement around that issue today."
Mr Duncan Smith added: "We also went on to discuss what the alternative arrangements were and what possibilities there were around the border.
"It was a pretty open and straightforward conversation. We are going to let the government know when we get back what was said."
Mr Paterson said that everyone agreed there should be no hard infrastructure on the Irish border. He said alternative technological arrangements were "the only show in town to resolve this issue".
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Activated if a wider EU/UK trade deal fails to materialise before the end of the Brexit implementation period, the backstop would see the UK enter into a temporary customs union with the EU, to avoid the need for customs checks on the Irish border.
It would also see Northern Ireland adhere to EU single market rules on goods, to rule out the necessity for border regulatory checks.
The DUP believes binding Northern Ireland to single market rules would create a regulatory border between the region and the rest of the UK - a move, it argues, that would undermine the constitutional integrity of the Union.
After the Brussels talks, Mrs Foster said Mrs May should use the extra six months now available to her to reopen the issue of the backstop.