Northern Ireland’s Democratic Unionist Party has struck out at the EU and the Irish Republic over the stalling of Brexit negotiations, but said it backs a "sensible Brexit" and will continue to work with the government on the issue.
Deputy leader Nigel Dodds said the integrity of the United Kingdom must be maintained, after the party scuppered a potential deal with Brussels that would have left Northern Ireland with different regulations from the mainland.
"The DUP does stand strong for the Union," he said.
"And we also issue a warning today to the Dublin government - that by continuing its aggressive stance they are in danger of delivering for themselves the very outcomes that they said they want to avoid."
It came as the Irish leader Taoiseach Leo Varadkar said he was confident that a deal could be salvaged before the end of the year as he pressed the UK to come up with a solution.
"I look forward to hearing from them as to how they think we can proceed. The ball is now in London's court," he said.
Theresa May's planned Brexit offer had to be abandoned at the eleventh hour after the DUP objected to wording that supposedly left Northern Ireland aligned with EU customs regulations while the rest of the UK was not.
The deal had been drafted to meet Ireland's demands to avoid a hard border - but the DUP made it clear they would withdraw support for Theresa May's Government if their requirements were not met.
Mr Dodds shrugged off suggestions that the move showed the DUP effectively had a veto over the government's Brexit negotiations.
He said they do not want a "no deal Brexit" as he again sought to blame the Irish Republic for "using their current position to try to gain wins for them".
"I don't argue with their desire to advance their interests, but they're doing so in a reckless and dangerous way which is putting at risk years of good Anglo-Irish relations and good cooperation within Northern Ireland."
Meanwhile, Irish Taoiseach Mr Varadkar said he believes a deal could still be salvaged before EU leaders meet at a summit on December 14.
He said the agreement on Monday had three possible options - An EU-UK free trade agreement that would allow free trade to continue between Britain and Ireland; a bespoke arrangement involving technology; or, if all else fails, an ongoing regulatory alignment between the north and south.
Former Northern Ireland secretary Lord Hain said the scenes in Brussels had been a "car crash" which could have been foreseen by anyone with knowledge of Irish politics.
"Unionists were quite legitimately always going to insist that they could not be put in a status distinct from the rest of the UK," he said at question time in the Lords.
In the Commons, Brexit Secretary David Davis faced stinging criticism from MPs as Labour labeled the government's Brexit negotiations an "embarrassment".
Mr Davis was responding to an urgent question raised by his Labour counterpart Keir Starmer.
In a heated exchange, Mr Starmer called for the deadline of 29 March 2019 for the UK to exit the EU to be abandoned, and for options such as staying in the EU customs union "back on the table".
He also said the collapse of the talks showed that the "DUP tail is wagging the Tory dog".
Mr Davis defended the governments efforts in the talks, insisting that "progress has been made" and saying he believed the first phase of the talks was now close to concluding.
"All parties remain confident of a positive conclusion by the end of the week," he said.
He said the government had no intention of allowing "one part of the United Kingdom" to remain inside the single market and customs union when Britain leaves the EU.
"That is emphatically not something that the UK government is considering," he said.